KR100809939B1 - Multi-staged catalyst systems and process for converting alkanes to alkenes and to their corresponding oxygenated products - Google Patents

Abstract

Corresponding oxygenation further using short contact time reactor conditions to form one or more catalysts to form corresponding alkenes by vapor cracking of the alkanes under the flame temperature and short contact times, and in cooperation therewith for short catalytic time reactor conditions. Multistage catalyst systems and multistage methods comprising forming the resulting product are used to prepare the gradual alkenes, unsaturated carboxylic acids, saturated carboxylic acids and their higher analogs from the corresponding alkanes.

Alkanes, Alkenes, Carboxylic Acids, Multistage Catalyst Systems

Description

MULTI-STAGED CATALYST SYSTEMS AND PROCESS FOR CONVERTING ALKANES TO ALKENES AND TO THEIR CORRESPONDING OXYGENATED PRODUCTS}

The present invention is a priority application of US Provisional Patent Application No. 60 / 523,297 filed on November 18, 2003.

The present invention relates to a process for the conversion of alkanes and oxygen to dehydrogenated and / or oxygenated products of alkanes and oxygen at catalyst and flame temperatures. More specifically, the present invention relates to a multi-step process that includes, but is not limited to, converting alkanes to corresponding alkenes by steam distillation followed by converting alkenes to corresponding oxygenated products under short contact time reactor conditions. In addition, the present invention provides a specific alkane at its flame temperature, in a short contact time reactor, oxygen containing the corresponding alkenes and unsaturated carboxylic acids, saturated carboxylic acids, esters of unsaturated carboxylic acids and their respective higher analogs. Catalytic system for conversion to cargo; A method for producing a catalyst system; And a hybrid for gas catalytic catalytic oxidation of alkanes using a catalyst system. The invention also relates to a catalyst system for the conversion of saturated carboxylic acids to their corresponding unsaturated carboxylic acids and higher analogue esters of unsaturated carboxylic acids and to a multistage process for the gas catalytic oxidation of saturated carboxylic acids. The present invention also provides a gas of alkanes comprising a step of an additional feed comprising alkenes, oxygen, formaldehyde and alcohols to produce unsaturated carboxylic acids, esters of unsaturated carboxylic acids and their respective higher analogs using a catalyst system. A multistage method for oxidation.

Selective partial oxidation of alkanes to unsaturated carboxylic acids and their corresponding esters is an important commercial method. However, selective oxidation / dehydrogenation of alkanes to products including olefins, unsaturated carboxylic acids and esters of unsaturated carboxylic acids has a number of important industrial problems to overcome. One limitation of oxidative dehydrogenation at short contact times of alkanes is in the first stage, ie, but not limited to, for example, carbon monoxide, carbon dioxide, water, alkanes debris (Cn-m) and alkenes (C2n-m). Because of several competing reactions beyond the oxidation reaction leading to), a lower yield is associated with the conversion of alkanes to their corresponding alkenes. The relatively low selectivity using mixed metal oxidation catalysts that convert alkanes to their corresponding alkenes under short contact time reactor conditions results from several factors including, but not limited to: (a) flame Catalysts that produce temperature conditions tend to catalyze beyond the oxidation of alkanes; (b) relatively low alkanes / oxygen ratios require maintenance of flame temperature conditions, which also support oxidation of alkanes and corresponding alkenes. (C) Total reaction kinetics promote oxidation of alkanes to carbon monoxide and carbon dioxide above the preferred oxidized dehydrogenated compounds, including the corresponding alkenes.

U. S. Patent No. 5,705, 684 discloses a process for producing acrolein and acrylic acid from propane using different multimetal oxidation catalysts in each step. In the first step, propane is dehydrogenated with a Mo-Bi-Fe oxide catalyst to form propylene, and the propylene formed is used as a feed of an oxidation reactor containing a Mo-V oxide catalyst in step 2, and oxygen is brought into contact with Produces a mixture of acrolein and acrylic acid. However, the endothermic method requires hydrogen removal in the first step at high cost, making it difficult to synthesize on a commercial scale. In addition, the Mo-Bi-Fe oxidation catalyst is thermally unstable at the flame temperature. The inventor mixes the corresponding alkanes with their corresponding alkenes and unsaturated carboxylic acids, saturated carboxylic acids and unsaturateds, using a novel catalyst system at a flame temperature, in a short contact time reactor, mixed with the corresponding cracking stages of the alkanes in the initial stages. A unique, efficient and commercially available multistage solution has been developed that converts to oxygenated products including esters of carboxylic acids. In addition, catalysts for use in the multistage process were developed while being used to convert saturated carboxylic acids to their corresponding unsaturated carboxylic acids and higher analogue esters of unsaturated carboxylic acids in a short contact time reactor at flame temperatures. In order to increase the selectivity and total yield in catalytic conversion of alkanes to the corresponding alkenes, the inventors further comprise reacting the corresponding alkenes under additional short contact time reactor conditions to form the corresponding oxidized products after vapor cracking of the alkanes. Developed a multi-step method. In another multi-step process, for example, a small amount of the corresponding alkanes is reacted with a stoichiometric amount of oxygen sufficient to be totally oxidized to carbon dioxide and water. Hot gas vapor and steam of carbon dioxide is associated with cracking zones including conventional cracking known in the art. The heated steam has a dual purpose to heat the cracking catalyst bed and provide steam for the cracking method. The main amount of the corresponding alkanes remaining is mixed with the carbon dioxide vapor mixture under conditions of intense flow. The gas mixture is then contacted with the cracking catalyst to provide alkenes with higher yields and selectivity. The converted corresponding alkenes are further catalytically converted to the corresponding oxygenates under short contact time reactor conditions. In another multistage process, for example, alkenes produced by dehydrogenation of alkanes using such catalysts are often produced as chemical intermediates in the process by steam cracking and are not separated into oxygenated products prior to selective partial oxidation.

Some advantages of the present invention are, for example, energy savings by burning sacrificial alkanes for low capital investment, light off and heat generation based on reduced reactor size, the multi-stage method provides a first phase The need for additional steam transition process requirements and minimal catalyst investment and maintenance due to the generation of its own steam in the (cracking stage) includes, but is not limited to, the easy achievement of thermal limitations of alkene production.

The present invention provides a multistage catalyst system comprising: At least one cracking catalyst for converting alkanes to their corresponding alkenes at flame temperatures and short contact times, and at the flame temperatures and short contact times further their corresponding alkenes to their corresponding oxidized products (eg , At least one oxidation catalyst for converting to saturated carboxylic acids and unsaturated carboxylic acids, including but not limited to (a) Ag, Au, Ir, Ni, At least one metal selected from the group consisting of Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof and (b) metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and Further comprising at least one modifier selected from the group of metal oxides including mixtures thereof, (c) metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, their Binary mixtures, tricomponent mixtures thereof, and At least one metal oxide is not mixed or mixed, including four or more components of the mixture; The catalyst is here impregnated with a metal oxide support.

According to another embodiment, the multistage catalyst system comprises converting saturated carboxylic acid to its corresponding unsaturated carboxylic acid at a short contact time, comprising at least one oxide comprising Mo, Fe, P, V and mixtures thereof. To include additional catalysts

The present invention provides a multistage catalyst bed comprising the following for the gradual conversion of alkanes to their corresponding alkenes, saturated carboxylic acids and unsaturated carboxylic acids; (a) at least at flame temperatures and short contact times; A first catalyst layer comprising one steam cracking catalyst;

(b) at least one metal selected from the group consisting of (i) Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof, and (ii) metals Bi, In, Mg, P At least one modifier selected from the group of metal oxides including Sb, Zr, Group 1-3 metals, lanthanide metals and mixtures thereof, and (iii) metals Cd, Co, Cr, Cu, Fe, Mn A second catalyst layer comprising at least one metal oxide mixed or not mixed, including Ni, Nb, Ta, V, Zn, a mixture of two components thereof, a mixture of three components thereof, and a mixture of at least four components thereof; Wherein the catalyst of the first layer is impregnated in the metal oxide support;

(c) at least one metal oxide comprising metals Mo, Fe, P, V and mixtures thereof, wherein the catalyst of the third layer is impregnated in the metal oxide support and directed downstream from the second catalyst layer, Further downstream from the catalyst layer, the third catalyst layer increasing the total yield of unsaturated carboxylic acid from the corresponding alkane.

According to another embodiment, the catalyst bed comprises the following additional catalysts for converting saturated carboxylic acids to their corresponding higher analog unsaturated carboxylic acids and esters of unsaturated carboxylic acids at short contact times: metals V, Nb At least one metal oxide comprising Ta and mixtures thereof.

The present invention provides a multistage catalyst for the gradual conversion of alkenes to their corresponding unsaturated carboxylic acids, esters of unsaturated carboxylic acids and their respective higher analogs, comprising (a), (b) and (c) To provide a bed;

(a) a first catalyst layer comprising at least one vapor cracking catalyst at a flame temperature and a short contact time;

(b) at least one metal selected from the group consisting of (i) Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; and (ii) metals Bi, In, Mg, P, Further comprises at least one modifier selected from the group of metal oxides including Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof (iii) metals Cd, Co, Cr, Cu, Fe, Mn, Ni A second catalyst layer with or without mixing with at least one metal oxide, including Nb, Ta, V, Zn, a mixture of two components thereof, a mixture of three components, and a mixture of four or more components thereof; The first catalyst layer is progressively efficient at converting the alkene to the corresponding saturated and unsaturated carboxylic acids, the catalyst of the first layer being impregnated in the metal oxide support;

 (c) converting the saturated carboxylic acid and the unsaturated carboxylic acid into the corresponding saturated higher analog unsaturated carboxylic acid in the presence of aldehyde, the ester of the corresponding unsaturated carboxylic acid in the presence of alcohol, and the formaldehyde and A third catalyst layer that is progressively effective in converting all of the alcohols to the corresponding higher analogs of unsaturated carboxylic acids in the presence.

In one embodiment, the second catalyst layer comprises one or more superacids and is self-supporting or optionally impregnated with a metal oxide support, the second catalyst layer being a corresponding ester, higher analog of unsaturated carboxylic acid. It is located in the lower part to increase the total yield of unsaturated carboxylic acid and its esters.

In one embodiment, additional feeds are incorporated including alkenes, oxygen, formaldehyde and alcohols to produce unsaturated carboxylic acids, esters of unsaturated carboxylic acids and their respective higher analogs using a catalyst system ( Or staging). Formaldehyde staged between the two catalyst layers produces the corresponding higher analog unsaturated carboxylic acid (Cn + C ₁ ). For example, the first catalyst converts propane (C ₃ alkanes) to propionic acid (C ₃ saturated carboxylic acid) and the second catalyst converts propionic acid in the presence of formaldehyde to higher analog methacrylic acid (C _4). Unsaturated carboxylic acid).

In another embodiment, the staged alcohol and sparged formaldehyde between the two catalyst beds produce higher analogue esters of the corresponding unsaturated carboxylic acids. For example, the first catalyst converts propane (C ₃ ) to propionic acid (C ₃ ) and the second catalyst converts propionic acid (C ₃ ) to methyl methacrylate (C ₄ ) in the presence of formaldehyde and methanol.

The present invention provides a multistep process for preparing the corresponding alkenes from alkanes comprising the following steps (a), (b) and (c);

(a) 5-30% by weight of gas alkanes and a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in vapor form;

(b) mixing vapor and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one vapor cracking catalyst;

(c) at least one metal selected from the group consisting of (a) Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; (b) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide-based metals and mixtures thereof, the gas alkanes corresponding thereto Mixing in a short contact time reactor including a catalyst system that is increasingly effective at converting to gas alkenes;

The reactor here operates at temperatures between 700 ° C. and 1000 ° C. and has a residence time of the reactor no greater than 100 milliseconds.

The present invention provides a multistep process for preparing the corresponding unsaturated carboxylic acids from alkanes comprising the steps of (a), (b) and (c);

(a) passing 5-30% by weight of gas alkanes and a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in the form of steam;

(b) mixing steam and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one steam cracking catalyst;

(c) at least one selected from the group consisting of (i) Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof, the gaseous mixture and molecular oxygen produced from (b) And (ii) at least one modifier selected from the group of metal oxides, including (ii) metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof, and (iii) Mixed or mixed with at least one metal oxide, including metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, mixtures of two components thereof, mixtures of three components and mixtures of four or more thereof A first catalyst layer impregnated with a metal oxide support; And (2) a second catalyst layer comprising at least one metal oxide containing Mo, Fe, P, V, and mixtures thereof, to gradually convert the gas alkenes to the corresponding gaseous unsaturated carboxylic acids. Catalyst mixing in a short contact time reactor with an effective mixed bed catalyst;

Wherein the second catalyst bed is at a distance from the lower part of the first catalyst bed and the reactor has a reactor residence time no greater than 100 milliseconds and is operated at a temperature of 500 to 1000 ° C .; One or more cracking catalysts are provided that include a distance of upstream portion from a short contact time reactor.

In another embodiment, the present invention provides for preparing a corresponding unsaturated carboxylic acid from an alkane comprising the following steps (a), (b), (c) and (d):

(a) passing 5-30% by weight of gas alkanes and a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in the form of steam;

(b) mixing vapor and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one vapor cracking catalyst;

(c) the gas mixture and molecular oxygen produced from (b) are catalytically mixed in a short contact time reactor comprising a mixed catalyst bed comprising at least one catalyst zone, wherein the first catalyst zone is (1 ) At least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof and (2) metals Bi, In, Mg, P, Sb, Zr, groups 1-3 further comprising at least one modifier selected from the group of metal oxides including metals, lanthanide metals and mixtures thereof, and (3) metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Or not mixed with at least one metal oxide, including Ta, V, Zn, a mixture of two components thereof, a mixture of three components, and a mixture of four or more components thereof, and the catalyst converts gaseous alkenes to the corresponding gaseous unsaturated carboxylic acids and With gaseous vapor containing saturated carboxylic acid And ring;

(d) a catalyst containing at least one metal oxide comprising metals Mo, Fe, P, V and mixtures thereof and impregnated in the metal oxide support, the gaseous saturated carboxylic acid having a corresponding gas desaturation Passing said gas vapor through a second catalyst zone that is progressively effective for conversion to carboxylic acid;

Wherein the at least one cracking catalyst is located at a distance relative to the upstream portion relative to the flow direction of the gas vapor relative to the first and second catalyst zones comprising a short contact time reactor;

The first catalyst zone is disposed upstream of the second catalyst zone with respect to the direction of flow of gas vapor through the reactor;

The first catalyst zone is operated in a temperature range of 500-1000 ° C. with a first reaction zone residence time not greater than 100 milliseconds;

The second catalyst zone has a second reaction zone residence time not greater than 100 milliseconds and is operated in a temperature range of 300 to 400 ° C;

Wherein the gaseous vapors of alkenes are passed through the reactor in one pass or the unreacted alkenes are returned to the gaseous vapors of alkenes entering the reactor, and the saturated carboxylic acid is returned to the second catalyst zone to increase the total yield of unsaturated carboxylic acids. Goes.

The present invention provides for the conversion of alkanes to esters of the corresponding unsaturated carboxylic acids.

(a) passing 5-30% by weight of gas alkanes, and a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in the form of vapor;

(b) mixing steam and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one steam cracking catalyst;

(c) the corresponding alkene and molecular oxygen produced from (b) is at least one selected from the group consisting of (1) (i) Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof At least one modifier selected from a group of metals, including one metal and (ii) metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof, (iii ) Mixed with at least one metal oxide, including metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, mixtures of two components thereof, mixtures of three components and mixtures of four or more thereof Gradually effective in converting unmixed gas alkanes to the corresponding gaseous unsaturated carboxylic acids, the catalyst of the first layer comprising: a first catalyst layer impregnated in the metal oxide support; And (2) a mixed catalyst bed comprising a mixed catalyst bed containing a second catalyst layer comprising at least one catalyst that is gradually effective in converting the gaseous unsaturated carboxylic acid to its corresponding gas ester. To;

 Wherein the second catalyst bed is at a distance from the lower part of the first catalyst bed and the reactor has a reactor residence time no greater than 100 milliseconds and is operated at a temperature of 500 to 1000 ° C .; One or more cracking catalysts are present at some distance to the upstream portion with respect to the flow of gaseous vapor of the reactants from the short contact time reactor.

In one embodiment, an additional catalyst layer is included between the first layer and a second layer containing at least one metal oxide comprising at least metals Mo, Fe, P, V, and mixtures thereof. The catalyst in the bed is progressively effective in converting the gas saturated carboxylic acid to its corresponding gas unsaturated carboxylic acid.

The present invention provides a process for converting an alkane to an ester of the corresponding unsaturated carboxylic acid, comprising the following steps (a), (b), (c), (d), and (e);

(a) passing 5-30% by weight of gas alkanes and a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in the form of steam;

(b) mixing vapor and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one vapor cracking catalyst;

(c) catalytic mixing of the corresponding alkene and molecular oxygen produced from (b) in a short contact time reactor comprising a mixed catalyst bed comprising at least one catalyst zone, wherein the first catalyst zone is ( 1) at least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; And (2) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof, (3) Mixed with at least one metal oxide comprising a metal Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, a mixture of two components thereof, a mixture of three components and a mixture of four or more thereof Unmixed, the catalyst converts the gas alkene into a gas vapor comprising corresponding gaseous unsaturated carboxylic acids and saturated carboxylic acids;

(d) a catalyst containing at least one metal oxide comprising metals Mo, Fe, P, V and mixtures thereof and impregnated in the metal oxide support, the gaseous saturated carboxylic acid having a corresponding gas unsaturated carboxyl Passing the gas vapor through a second catalyst zone that is gradually effective to convert to acid;

(e) passing a second gas vapor containing alcohol through the reactor;

Wherein the one or more cracking catalysts are located at a distance relative to the upstream portion relative to the flow direction of the gas vapor relative to the first and second catalysts in the first and second catalyst zones including the short contact time reactor;

The reactor comprises at least one oxidation catalyst which is progressively effective in converting the alkene together with the alcohol to the ester of its corresponding unsaturated carboxylic acid;

The at least one oxidation catalyst converts the alkanes into their corresponding unsaturated carboxylic acids with a first catalyst system, and the conversion of ethylenically unsaturated alcohols in the presence of alcohols to esters of the corresponding ethylenically unsaturated carboxylic acids with alcohols. And a second catalyst effective to

The first catalyst is disposed in the first reaction zone;

The second catalyst is disposed in the second reaction zone;

The first reaction zone is disposed upstream of the second catalyst zone with respect to the flow direction of the first gas vapor passing through the reactor;

The second gaseous vapor is fed into the reactor which mediates the first reaction zone and the second reaction zone;

The first reaction zone is operated in a temperature range of 500 to 1000 ° C. with a first reaction zone residence time not greater than 100 milliseconds;

The second reaction zone has a second reaction zone residence time no greater than 100 milliseconds and is operated in a temperature range of 300 to 400 ° C.

The present invention provides a multistep process for preparing higher unsaturated carboxylic acids comprising the following steps (a), (b), (c), (d), (e) and (f);

(a) passing 5-30% by weight of gas alkanes and a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in the form of steam;

(b) mixing vapor and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one vapor cracking catalyst;

(c) catalytic mixing of the gas mixture and molecular oxygen produced from (b) in a short contact time reactor comprising a mixed catalyst bed comprising at least one catalyst zone, wherein the first catalyst zone is (1 ) At least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; And (2) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof, (3) Mixed or mixed with at least one metal oxide, including metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, mixtures of two components thereof, mixtures of three components and mixtures of four or more thereof The catalyst converts the gas alkene into a gas vapor comprising corresponding gaseous unsaturated carboxylic acids and saturated carboxylic acids;

(d) a catalyst containing at least one metal oxide comprising metals Mo, Fe, P, V and mixtures thereof and impregnated in the metal oxide support, the gaseous saturated carboxylic acid corresponding thereto being Passing the gas vapor through a second catalyst zone that is gradually effective to convert to acid;

(e) passing a first gas vapor comprising alkanes and molecular oxygen through the reactor;

(f) passing a second gas vapor containing aldehyde through the reactor;

Wherein the one or more cracking catalysts are located at a distance relative to the upstream portion relative to the flow direction of the gas vapor relative to the first and second catalysts in the first and second catalyst zones including the short contact time reactor;

The reactor comprises one or more oxidation catalysts that are progressively effective in converting the alkanes to the corresponding higher analogs of unsaturated carboxylic acids;

The at least one oxidation catalyst converts the alkanes into their corresponding saturated carboxylic acids with the first catalytic system, and the saturated carboxylic acids with corresponding aldehyde higher analog unsaturated carboxylic acids in the presence of aldehydes. And a second catalyst effective to

The first catalyst is disposed in the first reaction zone;

The second catalyst is disposed in the second reaction zone;

The first reaction zone is disposed upstream of the second catalyst zone with respect to the flow direction of the first gas vapor passing through the reactor;

The second gaseous vapor is fed into the reactor which mediates the first reaction zone and the second reaction zone;

The first reaction zone is operated in a temperature range of 500 to 1000 ° C. with a first reaction zone residence time not greater than 100 milliseconds;

The second reaction zone has a second reaction zone residence time no greater than 100 milliseconds and is operated in a temperature range of 300 to 400 ° C.

The present invention provides a multistep process for converting alkanes to the corresponding unsaturated carboxylic acids, comprising the steps of (a), (b), (c), and (d);

(a) passing 5-30% by weight of gas alkanes and a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in vapor form;

(b) mixing vapor and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one vapor cracking catalyst;

(c) catalytic mixture of the gas mixture and molecular oxygen produced from (b) in a short contact time reactor comprising a mixed catalyst bed comprising at least one catalyst zone, wherein the first catalyst zone is (1 ) At least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; And (2) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof, (3) Mixed with at least one metal oxide, including metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, mixtures of their two components, mixtures of their three components and mixtures of four or more thereof Unmixed, the catalyst converts the gas alkene into a gas vapor comprising corresponding gaseous unsaturated carboxylic acids and saturated carboxylic acids;

(d) a catalyst containing at least one metal oxide comprising metals Mo, Fe, P, V and mixtures thereof and impregnated in the metal oxide support, the gaseous saturated carboxylic acid corresponding thereto being Passing the gas vapor through a second catalyst zone that is gradually effective to convert to acid;

Wherein the at least one cracking catalyst is located at a distance relative to the upstream portion relative to the flow direction of the gas vapor relative to the first and second catalysts in the first and second reaction zones including the short contact time reactor;

The reactor comprises at least one oxidation catalyst which is progressively effective in converting the alkene to the corresponding unsaturated carboxylic acid;

The at least one oxidation catalyst comprises at least one vapor cracking catalyst effective to convert alkanes to their corresponding alkenes, first and second catalysts effective to convert alkenes to the corresponding saturated and unsaturated carboxylic acids, and A third catalyst effective to convert the saturated carboxylic acid into the corresponding unsaturated carboxylic acid;

The first catalyst is disposed in the first reaction zone;

The second catalyst is disposed in the second reaction zone;

The third catalyst is disposed in the third reaction zone;

The first reaction zone is disposed upstream of the second reaction zone with respect to the flow direction of the first gas vapor passing through the reactor;

The second reaction zone is disposed upstream of the third reaction zone with respect to the flow direction of the first gas vapor passing through the reactor;

The second gas vapor is fed to a reactor which mediates the second reaction zone and the third reaction zone;

The first reaction zone is operated in a temperature range of 500 to 1000 ° C. with a first reaction zone residence time not greater than 100 milliseconds;

The second reaction zone has a second reaction zone residence time no greater than 100 milliseconds and is operated in a temperature range of 300 to 400 ° C.

The third reaction zone has a third reaction zone residence time no greater than 100 milliseconds and is operated in a temperature range of 100 to 300 ° C.

The present invention provides a multistep process for converting an alkane to a corresponding higher unsaturated carboxylic acid comprising the following steps (a), (b), (c), (d), and (e);

(a) passing 5-30% by weight of gas alkanes and a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in vapor form;

(b) mixing vapor and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one vapor cracking catalyst;

(c) catalytic mixing of the gas mixture and molecular oxygen produced from (b) in a short contact time reactor comprising a mixed catalyst bed comprising at least one catalyst zone, wherein the first catalyst zone is (1 ) At least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; And (2) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof, (3) Mixed or mixed with at least one metal oxide, including metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, mixtures of two components thereof, mixtures of three components and mixtures of four or more thereof The catalyst converts the gas alkene into a gas vapor comprising corresponding gaseous unsaturated carboxylic acids and saturated carboxylic acids;

(d) a catalyst containing at least one metal oxide comprising metals Mo, Fe, P, V and mixtures thereof and impregnated in the metal oxide support, the gaseous saturated carboxylic acid corresponding thereto being Passing the gas vapor through a second catalyst zone that is gradually effective to convert to acid;

(e) passing a second gas vapor containing aldehyde through the reactor;

Wherein the at least one cracking catalyst is located at a distance relative to the upstream portion relative to the flow direction of the gas vapor relative to the first and second catalysts in the first and second reaction zones including the short contact time reactor;

The reactor comprises one or more oxidation catalysts which are progressively effective in converting the alkanes to their corresponding unsaturated carboxylic acids with aldehydes;

The at least one oxidation catalyst comprises a first catalyst effective to convert alkanes to their corresponding alkenes, a second catalyst effective to convert alkenes to their corresponding saturated carboxylic acids, and saturated carboxylic acids in the presence of aldehydes. A third catalyst effective for converting to the corresponding higher analog unsaturated carboxylic acid;

The first catalyst is disposed in the first reaction zone;

The second catalyst is disposed in the second reaction zone;

The third catalyst is disposed in the third reaction zone;

The first reaction zone is disposed upstream of the second reaction zone with respect to the flow direction of the first gas vapor passing through the reactor;

The second reaction zone is disposed upstream of the third reaction zone with respect to the flow direction of the first gas vapor passing through the reactor;

The second gas vapor is fed to a reactor which mediates the second reaction zone and the third reaction zone;

The first reaction zone is operated in a temperature range of 500 to 1000 ° C. with a first reaction zone residence time not greater than 100 milliseconds;

The second reaction zone has a second reaction zone residence time no greater than 100 milliseconds and is operated in a temperature range of 300 to 400 ° C.

The third reaction zone has a third reaction zone residence time no greater than 100 milliseconds and is operated in a temperature range of 100 to 300 ° C.

The present invention provides a multistep process for converting alkanes to higher analogue esters of the corresponding unsaturated carboxylic acids, comprising steps (a), (b), (c), (d), (e) and (f). do;

(a) passing 5-30% by weight of gas alkanes and a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in vapor form;

(b) mixing vapor and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one vapor cracking catalyst;

(c) catalytically mixing the gas mixture and molecular oxygen resulting from (b) in a short contact time reactor comprising a mixed catalyst bed comprising at least one catalyst zone, wherein the first catalyst zone is (1) at least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; And (2) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof, (3) Mixed with at least one metal oxide, including metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, mixtures of their two components, mixtures of their three components and mixtures of four or more thereof Unmixed, the catalyst converts the gas alkene into a gas vapor comprising corresponding gaseous unsaturated carboxylic acids and saturated carboxylic acids;

(d) a catalyst containing at least one metal oxide comprising metals Mo, Fe, P, V and mixtures thereof and impregnated in the metal oxide support, the gaseous saturated carboxylic acid corresponding thereto being Passing the gas vapor through a second catalyst zone that is gradually effective to convert to acid;

(e) passing a second gas vapor containing formaldehyde containing aldehyde through the reactor;

(f) passing a third gas vapor containing alcohol through the reactor;

Wherein the reactor comprises one or more oxidation catalysts which are progressively effective in converting the alkanes to higher analogue esters of the corresponding unsaturated carboxylic acids with aldehydes and alcohols;

The one or more oxidation catalysts comprises a first catalyst effective for converting the alkanes to the corresponding saturated carboxylic acid, a second catalyst and an alcohol effective for converting the saturated carboxylic acid to the corresponding higher analog unsaturated carboxylic acid in the presence of an aldehyde. A third catalyst effective for converting the higher analog unsaturated carboxylic acid underneath to the higher analog ester of the corresponding unsaturated carboxylic acid with alcohol;

The first catalyst is disposed in the first reaction zone;

The second catalyst is disposed in the second reaction zone;

The third catalyst is disposed in the third reaction zone;

Wherein the at least one cracking catalyst is located at a distance relative to the upstream portion relative to the flow direction of the gas vapor relative to the first and second catalysts in the first and second reaction zones including the short contact time reactor;

The first reaction zone is disposed upstream of the second reaction zone with respect to the flow direction of the first gas vapor passing through the reactor;

The second reaction zone is disposed upstream of the third reaction zone with respect to the flow direction of the first gas vapor passing through the reactor;

The second gaseous vapor is fed into the reactor which mediates the first reaction zone and the second reaction zone;

The third gas vapor feeds into the reactor which mediates the second reaction zone and the third reaction zone;

The first reaction zone is operated in a temperature range of 500 to 1000 ° C. with a first reaction zone residence time not greater than 100 milliseconds;

The second reaction zone has a second reaction zone residence time no greater than 100 milliseconds and is operated in a temperature range of 300 to 400 ° C.

The third reaction zone has a third reaction zone residence time no greater than 100 milliseconds and is operated in a temperature range of 100 to 300 ° C.

The present invention relates to (a) the conversion of alkanes to a corresponding product selected from alkenes using one or more vapor cracking catalysts; (b) using a catalyst system of the invention to convert alkenes into unsaturated carboxylic acids and higher Conversion to an additional oxygenate selected from analog unsaturated carboxylic acids; (c) adding the resultant product or product to the front end of the second fixed bed oxidation reactor under short contact time conditions with the product of the first steam cracking reactor which feeds the secondary reactor. It provides a multi-stage recycling method comprising the step of. In one embodiment, the present invention comprises feeding unreacted alkenes in a first vapor cracking reactor and a short contact time reactor to a short contact time reactor for recycling the alkanes and alkenes, respectively. .

The present invention provides a counterpart selected from unsaturated carboxylic acids, higher derivative unsaturated carboxylic acids and esters thereof, the method comprising providing a thermal gradient having a gradual effect on enhancing the conversion of alkanes to preferably oxygenated products. It provides a multi-step method of converting the product to a product.

The present invention provides a catalyst cascade comprising the step of providing a catalyst cascade further comprising at least one catalyst system having a gradual effect in enhancing the conversion of alkanes to the desired oxygenated product. There is also provided a multistep process of converting analogue unsaturated carboxylic acids and their esters to their corresponding products selected.

As used herein, the term "multistage process" refers to the mixing of two or more stages, including two reactors, where each reactor comprises at least one catalyst, wherein the reactor comprises one or more alkanes as one or more corresponding oxygenated products. The method further comprises mixing at least one catalyst and at least one catalytic reactor in a short contact time reactor effective for gradual conversion.

In one embodiment, the multi-stage process includes a vapor cracking reactor that combines at least one catalyst in a short contact time reactor, a vapor cracking reactor that converts one or more alkanes into one or more corresponding alkenes, and one or more corresponding oxygenation of one or more corresponding alkenes. It is a multi-stage method comprising a short contact time reactor to convert to a converted product.

As used herein, the term "gradual conversion" means producing the desired product vapor from one or more specific reactants using the catalyst system of the present invention under specific reaction conditions. For illustrative purposes, for example, the gradual conversion of alkanes to esters of the corresponding unsaturated carboxylic acids with alcohols is carried out when the catalysts used are operated on feed vapors containing alkanes and alcohols under the reaction conditions devised. By means of producing a product vapor comprising an ester of an added alcohol with an unsaturated carboxylic acid corresponding to the added alcohol.

The term "catalyst system" as used herein means two or more catalysts. The term "multistage catalyst system" means one or more cracking catalysts mixed with one or more oxidation catalysts for the gradual conversion of alkenes to the corresponding oxygenated products. For example, platinum metal and indium oxide impregnated in an alumina support can be defined as a catalyst system. Another example is niobium oxide impregnated with platinum gauze. Another example is platinum metal, vanadium oxide and manganese oxide impregnated with silica.

Accordingly, the present invention relates to a multistage oxidation / dehydrogenation catalyst and multistage process for preparing dehydrogenated and oxygenated products from alkanes and oxygen with short contact times. Suitable alkanes include alkanes having straight or branched chains. Examples of suitable alkanes include C _3, such as C ₃ -C ₂₅ alkanes, preferably propane, butane, isobutane, pentane, isopentane, hexane and heptane - an ₈ alkane. Especially preferred alkanes are propane and isobutane.

The multistage catalyst system of the present invention converts alkanes into their corresponding alkenes and oxygenates, including saturated carboxylic acids, unsaturated carboxylic acids, esters thereof, and higher analog unsaturated carboxylic acids and esters thereof. The catalyst system is designed to provide specific alkenes, oxygenates and mixtures thereof. In one embodiment, the use of one or more conventional vapor cracking catalysts allows catalytic conversion of alkanes to the corresponding alkenes. The corresponding alkene produced in the cracking reactor is contacted with one or more oxidation catalysts to provide the corresponding oxygenate product in a short contact time reactor. In another embodiment, unreacted alkanes, alkenes or intermediates are recycled in accordance with the invention to catalyze it to its corresponding oxygenate. In a separate embodiment, dehydrogenation of the corresponding alkanes produced using the catalytic system or vapor cracking catalyst of the present invention is spontaneously produced as a chemical intermediate of the process and selective partial oxidation into additional corresponding oxygenated products. It is not separated into the corresponding alkene before it is. For example, when catalytic conversion of alkenes to their corresponding ethylenically unsaturated carboxylic acids is made, unreacted alkenes are recovered or recycled and catalytically converted to their corresponding ethylenically unsaturated carboxylic acid product vapors.

In one example of the invention, the alkanes are catalytically converted to their corresponding alkene intermediates when passing through two or more vapor cracking catalyst zones. For example, propane is converted to propylene through a steam catalytic reactor. In another example, the alkanes in the first and second stage catalyst zones or layers of the mixed hybrid catalyst bed are catalytically converted to the corresponding saturated carboxylic acids. In the presence of additional formaldehyde vapor, the saturated carboxylic acid in the second catalyst zone or bed of the mixed bed catalyst is converted to the corresponding higher analog ethylenically unsaturated carboxylic acid. In a specific example, propane is catalytically converted to propionic acid, and the propionic acid is catalytically converted to methacrylic acid in the presence of formaldehyde.

As used herein, the terms "higher analogue unsaturated carboxylic acids" and "esters of higher analogue unsaturated carboxylic acids" refer to products having at least one added carbon atom in the final product as compared to the alkane or alkene reactants. In the examples given above, propane (C ₃ alkane) is converted to propionic acid (C ₃ saturated carboxylic acid), and in the presence of formaldehyde, propionic acid is corresponding higher analog (C ₄ ) carboxyl using the catalyst of the present invention. Converted to acid, methacrylic acid.

Suitable alkenes used in the present invention include straight or branched chain alkenes. Examples of suitable alkenes include C ₃ -C ₂₅ alkenes, preferably C such as propene (propylene), 1-butene (butylene), 2-methylpropene (isobutylene), 1-pentene and 1-hexene ₃ -C ₈ alkene.

Suitable aldehydes used in the present invention include, for example, formaldehyde, ethanal, propanal and butanal.

The steam cracking catalyst system of the present invention converts alkanes to their corresponding alkenes. The oxidation catalyst system converts the corresponding alkenes into additional corresponding oxygenates comprising unsaturated and saturated carboxylic acids which are straight or branched chains. The multistage catalyst system catalyzes the conversion of the corresponding alkanes to the corresponding alkenes, further including but not limited to further corresponding oxygenates including unsaturated and saturated carboxylic acids which are straight or branched chains. For example, C ₃ -C ₈ saturated carboxylic acids such as propionic acid, butanoic acid, isobutyric acid, pentanoic acid and hexanoic acid. In one embodiment, the saturated carboxylic acids produced from the corresponding alkanes using the catalyst system of the present invention spontaneously produced as chemical intermediates in the process, and include unsaturated carboxylic acids, esters of unsaturated carboxylic acids, and unsaturated carboxylic acids. Oxygenated products, including higher esters, are not separated before selective partial oxidation. In another embodiment of the present invention, the resulting saturated carboxylic acid is converted to its corresponding product vapor including ethylenically unsaturated carboxylic acid, esters thereof, higher analog unsaturated carboxylic acids or esters thereof using the catalyst of the present invention. .

In one embodiment, a particular oxidation catalyst system gradually converts alkenes to their corresponding oxygenated products, and the multistage catalyst system of the present invention converts alkanes to their corresponding straight or branched chains of ethylenically unsaturated carboxylic acids and higher Incremental conversion to analogues. For example, C ₃ -C ₈ ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, butenoic acid, pentenonoic acid, hexenonoic acid, maleic acid and crotonic acid. The higher analog ethylenically unsaturated carboxylic acids are prepared from the corresponding alkanes and aldehydes. For example, methacrylic acid is prepared from propane and formaldehyde. In another embodiment, when preparing ethylenically unsaturated carboxylic acids from their respective alkanes, corresponding acid anhydrides are also produced. The catalysts of the present invention are useful for the conversion of propane to acrylic acid and its higher unsaturated carboxylic acids, methacrylic acid and the conversion of isobutane to methacrylic acid.

In one embodiment, certain oxidation catalyst systems of the present invention are used to convert alkenes to esters and higher analogs of the corresponding unsaturated carboxylic acids, and the multistage catalyst systems of the present invention also provide alkene to the corresponding unsaturated carbohydrates. Esters and higher analogs of acids can be used for gradual conversion. Specifically, these esters are butyl acrylate from butyl alcohol and propane, β-hydroxyethyl acrylate from ethylene glycol and propane, methyl methacrylate from methanol and isobutane, butyl methacrylate from butyl alcohol and isobutane , Β-hydroxyethyl methacrylate from ethylene glycol and isobutane, and methyl methacrylate from propane, formaldehyde and methanol.

In addition to these esters, other esters are formed by various kinds of alcohols introduced into the reactor throughout the present reaction and / or alkanes, alkenes and corresponding oxygenates introduced into the reactor.

Suitable alcohols include monohydric alcohols, dihydric alcohols and polyhydric alcohols. As a reference example of the monohydric alcohol, C ₁ -C ₂₀ alcohols, preferably C ₁ -C ₆ alcohols, most preferably C ₁ -C ₄ alcohols can be prepared but are not limited thereto. Monohydric alcohols include aromatic, aliphatic or aliphatic cyclic compounds; Straight or branched chain; Saturated or unsaturated; And primary, secondary or tertiary alcohols. Specifically preferred monohydric alcohols include methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol and t-butyl alcohol. As a reference example of the dihydric alcohol, C ₂ -C ₆ diols, preferably C ₂ -C ₄ diols, may be prepared but are not limited thereto. Dihydric alcohols may be aliphatic or aliphatic cyclic compounds; Straight or branched chain; And primary, secondary or tertiary alcohols. Particularly preferred dihydroxy alcohols are ethylene glycol (1,2-ethanediol), propylene glycol (1,2-propanediol), trimethylene glycol (1,3- propanediol), 1,2-butanediol and 2 , 3-butanediol. As a reference example of the polyhydric alcohol, gglycerol (1,2,3-propanetriol) can be prepared solely.

The unsaturated carboxylic acid corresponding to the added alkenes is an α, β-unsaturated carboxylic acid having the same carbon number as the starting alkanes and having the same carbon chain structure as the alkene, for example acrylic acid is an unsaturated carboxylic acid corresponding to propane. Methacrylic acid is an unsaturated carboxylic acid corresponding to isobutene.

Similarly, unsaturated carboxylic acids corresponding to alkenes are α, β-unsaturated carboxylic acids having the same number of carbon atoms as alkenes and carbon chains such as alkenes, for example, acrylic acid is unsaturated corresponding to propene. Carboxylic acid and methacrylic acid are unsaturated carboxylic acids corresponding to isobutene.
Similarly, unsaturated carboxylic acids corresponding to unsaturated aldehydes are α, β-unsaturated carboxylic acids having the same carbon number as unsaturated aldehydes and having the same carbon chain structure as unsaturated aldehydes, for example acrylic acid corresponding to acrolein. It is an unsaturated carboxylic acid, and methacrylic acid is an unsaturated carboxylic acid corresponding to methacrolein.

Alkenes corresponding to the added alkanes are alkenes having the same carbon number as the starting alkanes and having the same carbon chain structure as the starting alkanes, for example, propene is the alkenes corresponding to propane and isobutene corresponds to isobutane Alkenes (for alkenes having 4 or more carbon atoms, the double bond is at position 2 of the carbon-carbon chain of the alkene)

Unsaturated aldehydes corresponding to the added alkanes are α, β-unsaturated aldehydes having the same carbon atom number as the starting alkanes and having the same carbon chain structure as the starting alkanes; For example, acrolein is unsaturated aldehyde corresponding to propane and methacrolein is unsaturated aldehyde corresponding to isobutane.

Similarly, unsaturated aldehydes corresponding to added alkenes are α, β-unsaturated aldehydes having the same carbon atom number as the starting alkenes and having the same carbon chain structure as the starting alkenes; For example, acrolein is the unsaturated aldehyde corresponding to propene and methacrolein is the unsaturated aldehyde corresponding to isobutene.

With regard to the metals used as catalysts of the invention, the following definitions based on the periodic table apply:

Group 1 includes Li, Na, K, Rb and Cs.

Group 2 includes Mg, Ca, Sr and Ba.

Group 3 includes B, Al, Ga, In and Tl.

Lanthanide series metals are all stable elements of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and actinide series.

Group 4A includes C, Si, Ge, Sn and Pb.

Group 4B includes Ti, Zr, and Hf.

Group 5A includes N, P, As, Sb and Bi.

Group 5B includes V, Nb and Ta.

Group 6B includes Cr, Mo and W.

Group 7B includes Mn, Tc and Re.

Group 8 includes Fe, Ru, Os, Co, Rh, Ir, Ni, Pd and Pt.

Accordingly, the present invention provides a supported catalyst system for converting alkanes to their corresponding alkenes under vapor cracking conditions and converting alkenes to corresponding oxygenates with short contact times.

The support structure is three-dimensional, that is, the support is dimensioned along the x, y and z orthogonal axes of the Cartesian coordinate system and provides a relatively high surface area per unit volume. Although smaller and larger amounts are possible in one embodiment, the support structure exhibits a surface area of 0.01 to 50 m ² / g, preferably 0.1 to 10 m ² / g.

Preferably, the support structure has a porous structure and exhibits a void volume percentage of 1 to 95%, preferably 5 to 80%, more preferably 10 to 50%. Thus, the support structure allows a relatively high feed rate with a weak pressure drop.

In addition, the support structure is strong enough not to break up under the catalyst weight, so that up to almost 100% of the mixed weight of the catalyst and support structure does not break up. More preferably, the support structure is at least 60% of the mixing weight. More preferably 70 to 99.99% of the mixed weight. Even more preferably, the support structure is 90 to 99.9% of the mixed weight.

The exact physical form of the support structure is not particularly important as long as it meets the general criteria mentioned above. Examples of suitable physical forms include foams, honeycombs, grids, meshes, monoliths, woven fibers, woven fabrics, gauze, perforated materials (eg foils), particles Compact, fibrous mats and mixtures thereof. In the support, typically at least one open cell should be included in the structure. Cell size can be varied as desired, depending on cell density, cell surface area, open front area, and other corresponding dimensions. For example, one such structure has an open front area of at least 75%. The shape of the cell may vary and may include polygonal shapes, circles, ellipses, and the like.

The support structure can be made of a material that is inert to the reaction environment of the catalytic reaction. Suitable materials include ceramics and their isoforms such as silica, alumina (including α-, β- and γ- isoforms), silica-alumina, aluminosilicates, zirconia, titania, boria, and phylt ( mullite), lithium aluminium silicate, oxide-bonded silicon carbide, metal alloy monolith, Fricker type metal alloy, FeCrAl alloy, and mixtures thereof. Defined as such, it can be produced, for example, by "green" compacting (compression) or other suitable technique.)

The catalyst can be applied to the support structure using techniques known in the art. For example, the catalyst may be gas deposited (eg, sputtering, plasma welding or other forms of gas deposition). The catalyst can be impregnated or coated thereon (eg, by coating the support with a solution, slurry, suspension or dispersion of the catalyst). The support may be coated with catalyst powder (ie, powder coating). (Alternatively, the support structure may be compressed to produce a desired structure in which the "green" body of the catalyst, which is itself a catalyst.)

The multistage catalyst system of the present invention gradually converts alkanes to their corresponding alkenes and oxygenates. This vapor cracking catalyst comprises at least one cracking catalyst. Under a short contact time, the oxidation catalyst consists of three components: (a) at least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; And (b) at least one modifier selected from the group of metal oxides, including metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof. (C) at least one metal oxide comprising metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, mixtures of two components thereof, mixtures of three components and mixtures of four or more thereof It includes; The catalyst is impregnated into the metal oxide support.

Catalyst component (a) is a promoter useful for oxidatively dehydrogenating alkanes to form corresponding alkenes. The catalyst is present in the support in the form of finely dispersed metal particles comprising high surface area alloys (microns to nanometers). Alternatively, the catalyst is on the form of sophisticated gauze that includes nanometer-sized wire. The catalyst is impregnated onto the support using a technique selected from metal sputtering, chemical gas deposition, chemical and / or electrochemical reduction of metal oxides. Mixtures of promoters and their alloys may be useful. Catalyst system components include metal oxides used in admixture with metal oxides and promoters.

Catalyst component (b) is a modifier useful for partially oxidizing alkanes to form the corresponding saturated and unsaturated carboxylic acids. The metal oxide catalyst is in the form of a metal oxide mixed in two components, three components or four components or more. Reducible metal oxides are Bi, In, Mg, P, Sb, Zr, Group 1-3 metals, Sc, Y, La, Zr, Ta, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy , Ho, Er, Tm, Yb, Lu, and mixtures thereof. The modifier is preferably present in an amount of 0.0001 to 10% by weight of the catalyst composition (supercatalyst + reducible metal oxide), more preferably 0.001 to 5% by weight of the catalyst composition, more preferably 0.01 to 2 of the catalyst composition Present in weight percent.

The catalyst component (c) is mainly useful for partially oxidizing alkanes to form corresponding alkenes, saturated carboxylic acids and unsaturated carboxylic acids. The metal oxide catalyst is in the form of a two-, three- or four-component mixed metal oxide. Reducible metal oxides are Cu, Cd, Co, Cr, Fe, V, Mn, Ni, Nb, Mo, W, Re, Ga, Ge, In, Sn, Sb, Tl, Pb, Bi, Te, As, Se , An oxide of a metal selected from the group consisting of V, Zn, Y, Zr, Ta and mixtures thereof. Preferably, the reducible metal oxide is selected from the group consisting of metals Cd, Co, Cr, Cu, Fe, Mn, Ta, V and combinations thereof and mixtures thereof. The promoter is selected from the group consisting of Fe, Ru, Os, Co, Rh, Ir, Ni, Pd and Pt, preferably Pt, Pd, Rh, Ir, Ru and mixtures thereof. The cocatalyst is preferably present in an amount of 0.0001 to 10% by weight of the catalyst composition (cocatalyst + reducible metal oxide), more preferably 0.001 to 5% by weight of the catalyst composition, more preferably 0.01 to 5% of the catalyst composition. Present at 2% by weight. The catalyst is present in the support in the form of finely dispersed metal oxide particles (microns to nanometers) having a high surface area. The catalyst system component consists of the metal oxide and the metal oxide used in admixture with the promoter in contact with the metal oxide support.

In one embodiment, the catalyst system consists of catalysts (a) and (b). In another embodiment, the catalyst system comprises a mixture of catalysts (a), (b) and (c). The catalyst is in contact with a metal oxide support, which is typically a three-dimensional structure, and is preferably impregnated.

As mentioned above, the various mixed metal oxides of the present invention can be prepared by the following method.

In the first step, the slurry or solution may be formed by mixing the metal component, preferably the metal component comprising at least one oxygen and the at least one solvent in an appropriate amount to form the slurry or solution. It is preferable to form a solution at this stage of catalyst preparation. In general, metal compounds include the components required for the particular catalyst as previously defined.

Suitable solvents include water, alcohols (including but not limited to methanol, ethanol, propanol, diols, and the like) and other polar organic solvents known in the art. In general, water is preferred. Water may be any suitable water used for chemical synthesis, including but not limited to distilled and deionized water. The amount of water present is preferably an amount sufficient to allow the components in the substantial solution to remain for a time long enough to avoid or minimize phase separation of the composition and / or phase during the preparation step. Thus, the amount of water varies depending on the solubility and amount of the mixed material. However, as mentioned above, the amount of water is preferably sufficient to confirm that an aqueous solution is formed upon mixing.

For example, the structure of Mo _a V _b Te _c Nb _d O _e When mixed metal oxides are prepared, an aqueous solution of telluric acid, an aqueous solution of niobium oxalate and a solution or slurry of ammonium paramolybdate are added in turn to an aqueous solution comprising a predetermined amount of ammonium metavanadate, each The atomic ratio of the metal component is present at a predetermined ratio.

Once the aqueous slurry or solution (preferably solution) is formed, it is removed by any suitable method of forming catalyst precursors known in the art. Such methods include, but are not limited to, vacuum drying, freeze drying, spray drying, rotary evaporation, and air drying. Vacuum drying is generally carried out at pressures ranging from 10 mmHg to 500 mmHg. Freeze drying typically involves freezing the slurry or solution using, for example, liquid nitrogen, and drying the frozen slurry or solution under vacuum. Spray drying is generally performed under inert drying, such as nitrogen or argon, with an injection temperature of 125 to 200 ° C and an outlet temperature of 75 to 150 ° C. Rotary evaporation is generally carried out at a bath at a temperature of 25 to 90 ° C. and a pressure of 10 mmHg to 760 mmHg, preferably under a bath temperature of 40 to 90 ° C. and a pressure of 10 mmHg to 350 mmHg, more preferably 40 to 60 ° C. Bath temperature and a pressure of 10 mmHg to 40 mmHg. Air drying may be effective in a temperature range of 25 to 90 ° C. Rotary evaporation and air drying are commonly used.

Once the catalyst precursor has been obtained, the catalyst precursor is calcined. Firing is generally carried out in an oxidizing gas, but firing can also be carried out in a non-oxidizing gas (eg in an inert gas or in a vacuum). Inert gas means any material that is substantially inert, i.e., does not interact and react with the catalyst precursor. Suitable examples include, but are not limited to, nitrogen, argon, xenon, helium or mixtures thereof. Preferably the inert gas is nitrogen or argon. The inert gas may flow over the catalyst precursor surface but may not flow over it (static environment). When the inert gas passes over the surface of the catalyst precursor, the flow rate is in a wide range, for example from 1 to 1. It can be a variety of values above the space velocity of 500hr ⁻¹ .

Firing is mainly carried out at a temperature of 350 to 1000 ° C, including 400 to 900 ° C and 500 to 800 ° C. Firing is carried out for a time suitable to form the catalyst mentioned above. Firing is typically carried out in the range of 0.5 to 30 hours, preferably 1 to 25 hours, more preferably 1 to 15 hours to obtain the desired mixed metal oxide.

In one method of performance, the catalyst precursor is calcined in two stages. In the first step, the catalyst precursor is calcined under oxidizing gas for 15 minutes to 8 hours, including 1 to 3 hours, at a temperature of 200 to 400 ° C, including 275 to 325 ° C. In a second step, the material produced from the first step is calcined under non-oxidizing gas for 15 minutes to 8 hours, including 1 to 3 hours, at a temperature of 500 to 900 ° C, including 550 to 800 ° C.

Optionally, a reducing gas (eg ammonia or hydrogen) is added during the second stage firing.

In another method of performance, the catalyst precursor in the first stage is placed in the desired oxidizing gas at room temperature and then raised to the first stage firing temperature and maintained at that temperature for the desired first stage firing time. The gas is then replaced with non-oxidizing gas during the second stage firing and the temperature is raised to the desired second stage firing temperature and maintained at that temperature for the desired second stage firing time.

Although any type of heating mechanism (eg, furnace) is used during the firing process, it is desirable to perform the firing under the flow of the designed gaseous environment. Therefore, it is useful to fire in a bed where there is a continuous flow of the desired gas through the bed of solid catalyst precursor particles.

By firing, mixed metal oxidation catalysts are formed in stoichiometric or non stoichiometric amounts of each element.

The present invention also provides a mixed metal oxide catalyst and a process for preparing a metal oxide comprising the following steps of converting alkanes to their corresponding alkenes and oxygenates in a short contact time:

 Salts of metals selected from the group consisting of Mo, Te, V, Ta and Nb are mixed at a temperature above the melting point of the salt having the highest melting point to form a mixed molten salt;

In the presence of oxygen, the mixture of salts is calcined to provide a mixed metal oxidation catalyst, where a metal halide salt or metal oxyhalide salt may optionally be used as the solvent.

Starting materials for the mixed metal oxides are not limited to those mentioned above. Materials may be used, for example, but not limited to, oxides, nitrates, halides or oxy halides, alkoxides, acetylacetonates and organometallic compounds. For example, ammonium heptamolybdate can be used as a source of molybdenum as a catalyst. However, compounds such as MoO ₃ , MoO ₂ , MoCl ₅ , MoOCl ₄ , Mo (OC ₂ H ₅ ) ₅ , molybdenum acetylacetonate, phosphomolybdic acid and silicomolybic acid may also be used in place of ammonium heptamolybdate. Can be. Similarly, ammonium metavanadate may be used as a source of vanadium as a catalyst. However, compounds such as V ₂ O ₅ , V ₂ O ₃ , VOCl ₃ , VCl ₄ , VO (OC ₂ H ₅ ) ₃ , vanadinium acetylacetonate and vanadil acetylacetonate can be used instead of ammonium metavanadate. . Tellurium sources may include tereric acid, TeCl ₄ , Te (OC ₂ H ₅ ) ₅ , Te (OCH (CH ₃ ) ₂ ) ₄ and TeO ₂ . Niobium sources include ammonium niobium oxalate, Nb ₂ O ₅ , NbCl ₅ , niobic acid or Nb (OC ₂ H ₅ ) ₅ and conventional niobin oxalate.

The use of low melting salts enables new approaches for producing mixed metal oxide catalysts. Current aqueous suspension methods have the advantage of better mixing of insoluble metal salts, better control of metal ratio, and a more homogeneous catalyst system. One unique approach is to use a low melting halide of the preferred MMO metal to prepare a salt solution. The change in this approach is described in more detail below.

The halide salts of the preferred metals are mixed at temperatures above the melting point of the salt with the highest melting point. The molten salts must be able to be mixed with each other to form a stable, uniform solution of the molten salt.

The advantage of this method is that it removes the solubility limitations inherent in aqueous slurry systems. The use of molten salts makes it possible to mix metals such as salts, palladium, vanadium, niobium, which have relatively low solubility in aqueous media, at higher levels. Examples of metal salts and their melting points are shown in Table 4. Such salts are readily available, relatively inexpensive, and have a reasonably low melting point.

In one embodiment, certain metal oxyhalides are used as solvents in preparing metal oxides using the present invention. Vanadinium halides, such as vanadinium tetrachloride (VCl ₄ ) and vanadil trichloride (VOCl ₃ ), because of their polarity and low boiling point (BP (VCl ₄ ) = 148 ° C., BP (VOCl ₃ ) = 127 ° C.) It is a liquid at room temperature and is an ideal solvent for the clyde salts of other metals. The metal halide is dissolved in one of these solvents in the desired molar ratio, at which time excess vanadium is removed by evaporation under reduced pressure and inert atmosphere. The catalyst cake may be calcined under O ₂ / argon to produce a mixed metal oxide (MMO) catalyst and HCl. In addition, mixed metal halides (MMH) can also be converted to MMO, as described in more detail below.

In other embodiments, it is advantageous to introduce oxygen in the initial synthesis. This is obtained by mixing the metal oxide with either a molten salt solution or a VCl ₄ / VOCl ₃ solution. This method reduces the amount of chlorine that must be removed during firing and produces a mixed oxychloride precursor that already has some of the desired properties of the final catalyst. In one preparation, oxides of niobium, tellurium, and molybdenum are melted in VCl ₄ / VOCl ₃ . As a result, the precursor already contains a lot of oxygen.

In other embodiments, the mixed metal halides (MMH) can also be converted to MMO. Three methods of converting mixed metal halides (MMH) and mixed metal oxyhalides (MMOH) to mixed metal oxides (MMO) are described:

(A) MMH is calcined under wet (1%) argon at elevated temperature (600 ° C.). Off-gas is removed with caustic to trap product HCl.

(B) The MMH precursor is calcined with low O ₂ concentration under argon gas. Low O ₂ concentration is controlled in the reaction. Oxychloride gas is removed with caustic.

(C) The MMH precursor is chemically converted to a metal alkoxide under mild conditions and then calcined under O ₂ / argon to yield an MMO catalyst. By using an alkoxide intermediate, it can be changed to the crystal structure of the final catalyst.

MMOs prepared from the molten salt method can be prepared on support materials including metal oxide supports. One advantage of using molten salt or a salt solution in VCl ₄ / VOCl ₃ is that it is relatively easily impregnated into a support material such as alumina, zirconia, silica, or titanium oxide, and is used during pearl technique or continuous loading. Allow either use. The relatively high metal concentration in solution causes the metal, which provides the ideal catalyst in millisecond time contact reaction, to increase the metal loading on the support material.

Alternatively, another approach to providing a supported MMO catalyst is to add a finely divided support material such as aluminum oxide to the salt solution (molten salt or VCl ₄ / VOCl ₃ solution) to form a suspension / slurry. After concentration and firing, the final catalyst produced is a supported MMO catalyst with a fairly high surface area.

The mixed metal oxides obtained here show excellent catalytic activity by themselves. However, mixed metal oxides can be converted into catalysts having higher activity by grinding.

There is no particular limitation on the polishing method, and a conventional method can be used. In the dry polishing method, for example, a method using gaseous vapor abrasive may be mentioned, wherein the coarse particles collide with each other in the high speed gas vapor during polishing. Grinding can be carried out not only mechanically, but also using something like mortar in the case of small size work.

Polishing is a wet polishing method in which the polishing is performed in a wet state by adding water or an organic solvent to the mixed metal oxide, and a conventional method using a rotating cylinder-type intermediate mill or an intermediate-stirring type mill is mentioned. Can be. A rotary cylinder-type intermediate mill is a wet mill of the type in which a vessel containing a material to be milled is rotated, and includes, for example, a ball mill and a rod mill. The intermediate-stirrer type mill is a type of wet mill, in which the ground and container-containing materials are agitated by a stirring apparatus, for example rotary screw type mills and rotary disc type mills. Include.

Conditions for polishing include the properties of the metal oxides mentioned and mixed above; Viscosity, concentration, of solvent used for wet polishing; Or it is set according to the optimum condition of the jute machine. However, it is preferable to grind until the average particle size of the polished catalyst precursor is at most 20 μm, more preferably at most 5 μm. Such polishing can improve catalytic performance.

In addition, in some cases, the catalytic activity may be further improved by further adding a solvent to the polished catalyst precursor to form a solution or slurry and then drying again. There is no particular restriction on the concentration of the solution or slurry, but usually the solution or slurry results in a total amount of starting material compound of 10 to 60% by weight relative to the polished catalyst precursor. The solution or slurry is then dried by methods such as spray drying, freeze drying, evaporation for drying or vacuum drying. In addition, similar drying may also be performed when wet polishing is performed.

The oxide obtained by the above-mentioned method is used as the final catalyst, but may further be heat treated for 0.1 to 10 hours mainly in the temperature range of 200 to 800 ℃.

The mixed metal oxides thus obtained are typically used as solid catalysts per se, but may also form catalysts with suitable carriers such as silica, alumina, titania, aluminosilicate, silicon earth or zirconia. In addition, it may be molded to a suitable shape and particle size depending on the size or system of the reactor.

Alternatively, the metal components of the presently planned catalysts can be supported on materials such as alumina, silica, silica-alumina, zirconia, titania and the like. In one typical method, a solution comprising a metal is contacted with a dry support to cause the support to be wet; The resulting wetted material is then dried, for example, at room temperature to 200 ° C. and then calcined as mentioned above. In another method, the metal solution is contacted to the support typically in a volume ratio greater than 3: 1 (metal solution: support), and the solution is agitated to allow metal ions to ion exchange onto the support. The metal comprising the support is then dried and calcined as described above.

When using a catalyst system comprising two or more catalysts, the catalyst is in the form of a physical mixture of several catalysts. Preferably the concentration of the catalyst may be varied in order to have a tendency for the first catalyst component to be concentrated in the reactor injection followed by a tendency for the catalyst to be concentrated in sequential zones extending towards the reactor outlet. Most preferably, the catalyst is a bed (or mixed bed catalyst) formed of a bed with a first catalyst component forming a layer closest to the reactor inlet section and subsequent catalysts forming a continuous layer at the reactor outlet section. Are mentioned). The layers may be adjacent to each other or may be separated from each other by a layer or void of inert material.

Short contact time reactors are one type suitable for the use of fixed catalyst beds in contact with the gaseous vapors of the reactants. For example, shells and tubes of the reactor may be utilized, one or more tubes may be packed with a catalyst to allow reactant gas vapors to pass through one end of the tube (s), and the product may pass through the tubes ( From the other end of the A tube disposed in the cell for heat transfer medium to be circulated around the tube is circulated around the tube.

In the use of single catalysts, hybrid catalysts, catalyst systems or hybrid catalyst systems, alkanes, molecular oxygen and added reactant feeds (e.g. alkenes, oxygen, air, hydrogen, carbon monoxide, carbon dioxide, formaldehyde, And gas distillation, including but not limited to alcohol, vapor, and any diluent (including nitrogen, argon) can all be fed together to the front end of the tube.

Alternatively, molecular oxygen, including alkanes and gases, may be fed to the front end of the tube, and additional reactants, vapors, and diluents may be fed (or referred to as staging) into the tube at predetermined lower part locations. (Typically to have a certain minimum concentration of product alkene (eg, 3%, preferably 5%, most preferably 7%) present in the gas vapor passing through the tube.

In using a catalyst system comprising two or more catalysts (eg, the first and second catalyst components described above), alkanes, molecular oxygen and added reactant feeds (eg, alkenes, oxygen, air) Gas distillation, including, but not limited to, hydrogen, carbon monoxide, carbon dioxide, formaldehyde, and alcohol, vapor and any diluent (including nitrogen, argon) can all be fed together to the front end of the tube. have. Alternatively, molecular oxygen, preferably including alkanes and gases, can be fed to the front end of the tube, staging additional reactants, vapors and diluents into a tube at a predetermined lower part location (typically passing through the tube). To have a certain minimum concentration of the desired product present in the gaseous vapors (as mentioned above); or as mentioned above, in the use of a bed of catalyst beds which mediates a two-bed catalyst bed, do.

In addition to molecular oxygen, carbon dioxide acts as a milder oxidant in the multistage process of the present invention. One advantage of the present invention is that carbon dioxide is produced using a portion of alkanes at the beginning of steam cracking with the addition of steam using conventional steam cracking catalysts well known in the art. In addition to preparing mild oxides, the exothermic properties of converting alkanes to alkenes are minimized to eventually minimize oxidation beyond products including, but not limited to, carbon monoxide, alkanes and alkenes and mixtures thereof.

The second advantage is that unlike molecular oxygen, carbon dioxide does not induce gaseous radical reactions. Such oxidative couple reactions are controlled by heterogeneous catalysts. In the results and exemplary embodiments, methane can be oxidatively coupled without excessive oxidation to provide ethylene, such as methane and ethane being mixed and catalytically converted to propylene. Suitable catalysts include PbO / MgO, lanthanum based metal oxides, mixtures of lanthanum based metal oxides, CaO / CeO ₂ , metal oxides, mixtures of oxides of groups 1-3, and CaO / MnO ₂ , Cao / Cr ₂ O ₃ , CaO / ZnO, mixtures of metal oxides, multicomponent metal oxidation catalysts, supported metal oxides (such as those described earlier in SiO ₂ / Cr ₂ O ₃ ), certain non-metal oxides, certain non-oxides, and mixtures thereof It is not limited to this.

In another embodiment, the use of carbon dioxide and steam in a vapor cracking method of partially sacrificing some early alkanes and mixing the remaining alkanes and oxidants to produce some carbon dioxide as an oxidant at the expense of some initial alkanes (eg For example, but not limited to, ethane, propane, isobutane and butane) are oxidized to the corresponding alkenes. As described at the outset, another advantage of the present invention is to minimize the unwanted reactions that lead to coking at higher temperatures, to oxidize all of the molecular hydrogen, to allow it to be oxidized at lower temperatures, and further to peroxidation of alkanes. To minimize it. Suitable catalysts in addition to those described above include, for example, metal oxide catalysts, mixed metal oxide catalysts, multicomponent metal oxidation catalysts (K-Cr-Mn / SiO ₂ , SiO ₂ / Cr ₂ O ₃ and Fe / Mn). And supported mixtures described earlier, such as silicates) and mixtures thereof. The advantage of carbon dioxide as an oxidant is that its redox nature prevails in catalytic processes, including unwanted radical processes. Carbon dioxide produces reactive oxygen species that act as oxidants, carbon dioxide redoxes the reduced oxides that form a continuous redox cycle, and oxidizes the reduced cocking carbon. Typical conditions for oxidizing alkanes used in the practice of the present invention to the corresponding alkenes include a vapor cracking reaction that can vary widely from 200 to 700 ° C. Conventional steam cracking reactors and catalysts are well described in the journal Energy & Fuels, 18, 1126-1139, 2004 and are known in the art.

For example, typical reaction conditions for converting alkenes to acrylic and methacrylic acid comprising their respective esters used in the practice of the present invention, including but not limited to ethylene, propylene, butylene or isobutylene. Includes: The reaction temperature may vary from 0 to 1000 ° C., but mainly in the flame temperature (500 to 1000 ° C.) range; The time of contact with the catalyst is 100 milliseconds or less, including 80 milliseconds or less and 50 milliseconds or less; The pressure in the reaction zone is in the range of 0 to 75 psig, mainly including 50 psig or less.

The present invention comprises (a) mixing 5-30% by weight of gas alkanes with a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in vapor form;

(b) mixing vapor and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one vapor cracking catalyst;

(c) the gas mixture and molecular oxygen produced from (b) are mixed in a short contact time reactor comprising a mixed catalyst bed consisting of a first catalyst layer and a second catalyst layer, wherein (1) the first catalyst layer is (i) ) At least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; And (ii) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof, and (iii) metal Cd Or not mixed with at least one metal oxide, including Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, mixtures of two components thereof, mixtures of three components and mixtures of four or more thereof ; Wherein the catalyst of the first layer is impregnated in the metal oxide support; (2) the second catalyst layer contains at least one metal oxide comprising metals Mo, Fe, P, V and mixtures thereof, and the mixed bed catalyst converts the gas alkanes to the corresponding unsaturated carboxylic acids. Providing a multistage process for preparing the corresponding unsaturated carboxylic acid from an alkane, the step being progressively effective;

Wherein the second catalyst bed is located at a lower distance from the first catalyst bed at a lower distance and the reactor is operated in a temperature range of 500 to 1000 ° C. with a reactor residence time of less than 100 milliseconds; Wherein the one or more cracking catalysts are located in the upper part away from the reactor by a short contact time.

In another embodiment, the present invention relates to a process for the preparation of (a) 5-30 wt.

(b) mixing vapor and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one vapor cracking catalyst;

(c) the gas mixture and molecular oxygen resulting from (b) are mixed in a short contact time reactor comprising a mixed catalyst bed consisting of a first catalyst layer and a second catalyst layer, wherein (1) the first catalyst layer is (i) ) At least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; And (ii) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof, and (iii) metal Cd Or not mixed with at least one metal oxide, including Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, their two-component mixtures, their three-component mixtures and mixtures of four or more thereof; Wherein the catalyst of the first layer is impregnated in the metal oxide support; (2) the second catalyst layer contains at least one metal oxide comprising metals Mo, Fe, P, V and mixtures thereof, and the mixed bed catalyst converts the gas alkanes to the corresponding unsaturated carboxylic acids. Providing a multistage process for preparing the corresponding unsaturated carboxylic acid from an alkane, the step being progressively effective;

Wherein the at least one cracking catalyst is at a distance from the upper portion from the short term catalytic reactor;
The first catalyst is disposed in an upstream portion of the second catalyst zone with respect to the direction of flow of gas vapor through the reactor:

The first catalyst zone is operated at a first catalytic reaction zone residence time of less than 100 milliseconds and at a temperature of 500 to 1000 ° C;

The second catalyst zone is operated in a reactor residence time of less than 100 milliseconds and in a temperature range of 300 to 400 ° C;

Wherein the gaseous vapors of alkanes are passed through the reactor in a single pass, or are recovered with the gaseous flow of alkanes where unreacted alkanes enter the reactor, and saturated carboxylic acids increase the total yield of unsaturated carboxylic acids. To the second catalyst zone.

It is useful to pass a gas vapor containing propane or iso propane and oxygen molecules through the reactor. In addition, the feed may include additional reactants, auxiliaries such as steam or diluents such as inert gases (eg nitrogen, argon) or mild oxidants including carbon dioxide.

In another embodiment, the gaseous vapors of alkanes or alkenes are passed through SCR or SCTR in a single pass, respectively, or recovered as alkene gas vapors where unreacted alkanes or alkenes respectively enter SCTR and saturated carboxylic acids are recovered to the second catalyst zone. To increase the total yield of unsaturated carboxylic acids.

The present invention also provides a multistage process comprising the following methods: (a) gradually converting alkanes to their corresponding alkenes using one or more vapor cracking catalysts; (b) converting the corresponding alkenes to the catalyst system of the present invention. Catalytic conversion to further corresponding oxygenated products selected from unsaturated carboxylic acids, and higher analog unsaturated carboxylic acids in a short contact time reactor; (c) The resultant product or product is added to the front end of a second fixed bed oxidation reactor with the product from the first reactor serving as feed in the second reactor. For example, propane cranks the first vapor and catalytically converts it to propylene, which is further catalytically converted to the corresponding oxygenate using a catalyst system in a short contact time reactor. Propylene is fed to a second oxidation reactor that converts it to acrylic acid. In one embodiment, this comprises feeding unreacted alkanes from the first reactor and unreacted alkenes from the second reactor to recover the alkanes and alkenes, respectively. For example, unreacted propane is recovered in a first steam cracking reactor or SCR or optionally added as a feed to a second oxidation reactor. The second oxidation reactor includes a conventional industrial scale oxidation reactor used to convert alkenes to unsaturated carboxylic acids at longer residence times (seconds). Alternatively, the second oxidation reactor includes a second SCTR operation at millisecond residence time.

For example, oxygen, gas or air containing a large amount of oxygen may be applied during this method. In the absence of recovery, air can be the most economical source of oxygen.

Alternatively, the metal oxidation catalyst component or second catalyst layer may comprise:

(A) Mixed Metal Oxide Catalysts Having the Experimental Mo _a V _b M _c N _d O _e

Where M is selected from the group consisting of Te and Sb,

N is Nb, Ta, W, Ti, Al, Zr, Cr, Mn, B, In, As, Ge, Sn, Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, At least one element selected from the group consisting of Hf and P,

a, b, c, d and e represent the relative atomic weights of the elements

a = 1, b = 0.01 to 1.0, c = 0.01 to 1.0, d = 0.01 to 1.0 and e depend on the oxidation state of atoms other than oxygen.

At the flame temperature, certain metal components, including Mo or Te, of the mixed metal oxide catalysts volatilize the remaining mixed metal oxidation catalysts, intermetallic catalysts, and their hybrid catalysts.

(B) Mixed Metal Oxide Catalysts Having Experimental Mo _a Sb _b O _c

here

a, b, and c represent the relative atomic weights of the elements

a = 1, b = 0.01 to 1.0, and c depend on the oxidation state of atoms other than oxygen. At the flame temperature, certain metal components of the mixed metal oxide catalyst volatilize other mixed metal oxidation catalysts, intermetallic catalysts and their hybrid catalysts remaining.

(C) Mixed metal oxide catalyst with empirical formula Mo _a Sb _b Bi _c O _d

here

a, b, c and d represent the relative atomic weights of the elements

a = 1, b = 0.01 to 1.0, c = 0.01 to 1.0, d depends on the oxidation state of atoms other than oxygen. At the flame temperature, certain metal components of the mixed metal oxide catalyst volatilize other mixed metal oxidation catalysts, intermetallic catalysts and their hybrid catalysts remaining.

Alternatively, the catalyst may comprise a mixture of catalysts (A), (B) and (C).

Other alternative oxidation catalysts include:

(a) a support comprising at least one element selected from the group consisting of groups of groups 5B, 6B, 7B and 8 of the Periodic Table of the Elements promoted with at least one element selected from group 1B and bismuth oxide acetate of the Periodic Table of Elements Catalyst; or

(b) a catalyst comprising ruthenium; or

(c) a catalyst comprising Pd and Bi on a support; or

(d) support comprising at least one element selected from the group consisting of elements of groups 3A, 4A, 5A and 6B in Pd and the periodic table of elements and at least one element selected from the group consisting of elements of groups 3B and 4B in the periodic table of elements Catalyst; or

(e) a supported catalyst comprising Pd and at least one element of group 1B in the periodic table of elements; or

(f) a supported catalyst comprising Pd and Pb: or

(g) a supported catalyst comprising Pd and at least one element selected from the group consisting of Ba, Au, La, Nb, Ce, Zn, Pb, Ca, Sb, K, Cd, V and Te; or

(h) mixtures thereof.

Still other alternative catalysts include phosphate catalysts containing Mo, V, Nb and / or Ta. See Japanese Laid-Open Patent Application Publication No. 06-199731 A2]. Other alternative catalysts also include well known molybdenum, bismuth, iron-based mixed metal oxides, which are disclosed in US Pat. Nos. 3,825,600; 3,649,930 and 4,339,335.

The present invention also provides a multistep process for preparing esters of unsaturated carboxylic acids, comprising the following steps (a), (b) and (c).

(a) mixing 5-30% by weight of gas alkanes with a stoichiometric amount of molecular oxygen sufficient to completely oxidize the alkanes to carbon dioxide and water in vapor form;

(b) mixing vapor and residual amounts of alkanes with steam and carbon dioxide and contacting it with at least one vapor cracking catalyst;

(c) the corresponding alkene and molecular oxygen produced from (b) are mixed in a short contact time reactor comprising a mixed catalyst bed consisting of a first catalyst layer and a second catalyst layer, wherein (1) the first catalyst layer is (i) at least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; And (ii) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, group 1-3 metals, lanthanide metals and mixtures thereof, and (iii) metal Cd Or not mixed with at least one metal oxide, including Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn, their two-component mixtures, their three-component mixtures and mixtures of four or more thereof; Wherein the catalyst of the first layer is impregnated in the metal oxide support; (2) the second catalyst layer contains at least one metal oxide comprising metals Mo, Fe, P, V and mixtures thereof, and the mixed bed catalyst converts the gas alkanes to the corresponding unsaturated carboxylic acids. Gradual effective;

Wherein the at least one cracking catalyst is at a distance from the upper portion from the short term catalytic reactor;

The second catalyst bed is at a distance from the lower portion of the first catalyst bed and is operated at reactor residence time of 100 milliseconds or less and at a temperature of 500 to 1000 ° C.

In one embodiment, an additional catalyst layer can be included between the first and a second layer comprising at least one metal comprising metals Mo, Fe, P, V and mixtures thereof, wherein the catalyst of the added layer is Prior to being catalytically converted to the corresponding ester in the presence, it is a gradual effective to convert the gas saturated carboxylic acid to the corresponding gas unsaturated carboxylic acid.

The present invention also provides a multi-step process for the gradual conversion of alkanes to esters of the corresponding unsaturated carboxylic acids, the reactor being one that is effective in converting alkanes with esters of the corresponding carboxylic acids with alcohols. It includes the above oxidation catalyst; The at least one oxidation catalyst converts the ethylenically unsaturated alcohols into esters of the corresponding ethylenically unsaturated carboxylic acids with alcohols in the presence of an alcohol and a first catalyst system effective to convert the alkanes to their corresponding unsaturated carboxylic acids. An effective second catalyst;

The first catalyst is disposed in the first reaction zone;

The second catalyst is disposed in the second reaction zone;

The first reaction zone is disposed above the second reaction zone in relation to the flow direction of the first gas vapor passing through the reactor;

The second gas vapor is fed into the reactor intermediate of the first reaction zone and the second reaction zone;

The first reaction zone is operated in a first reaction zone residence time of less than 100 milliseconds and in a temperature range of 500-1000 ° C .;

The second reaction zone is operated in a second reaction zone residence time of less than 100 milliseconds and in a temperature range of 300 to 400 ° C.

In another embodiment, a multistage process is provided for catalytic and gradual conversion of alkanes to their corresponding higher unsaturated carboxylic acids and for catalytic conversion of them in the presence of specific alcohols.

In preparing esters of ethylenically unsaturated carboxylic acids and higher analogs thereof using the multistage catalyst system of the present invention, a first gas vapor comprising propane or isobutane and molecular oxygen is passed through SCR to form carbon dioxide, Useful for oxidizing the remaining alkanes to the corresponding alkenes, propylene and isobutylene; The corresponding alkenes are passed through SCTR with one or more oxidation catalysts to convert the gradual alkenes to the corresponding unsaturated carboxylic acids and a second gas vapor containing alcohol is passed separately to the reactor. In addition, the feed may include additional reactants, auxiliaries such as steam or diluents such as inert gases (eg nitrogen, argon) or additional oxidants including carbon dioxide. Additional reactant feeds may include, but are not limited to, alkenes, oxygen, air, hydrogen, carbon monoxide, carbon dioxide, and formaldehyde.

Useful to pass a first gaseous vapor comprising propane or isobutane and oxygen molecules to the SCR, then passing the corresponding alkene gaseous vapor to the SCTR; A second gaseous vapor containing alcohol and additional feeds is passed separately to the SCTR. In addition, the feed may comprise auxiliaries such as steam or diluents such as inert gases (eg nitrogen, argon or carbon dioxide).

Examples of sources of other mild oxidants, including molecular oxygen or carbon dioxide, which may be applied to the present invention, include oxygen, oxygen-rich gases, or air. Air is the most economical source of oxygen, especially in the absence of recovery.

Another first catalyst may comprise a mixed metal oxide catalyst having the empirical formula Mo _a V _b M _c N _d Q _e X _f O _g ;

Where M is an element selected from the group consisting of Te and Sb,

N is Nb, Ta, W, Ti, Al, Zr, Cr, Mn, B, In, As, Ge, Sn, Li, Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Ba, At least one element selected from the group consisting of Hf and P,

Q is at least one element selected from group 8 of the periodic table;

X is at least one element selected from the group consisting of Pd and Bi;

a, b, c, d, e, f and g represent the relative atomic weights of the elements

a = 1, b = 0.01 to 1.0, c = 0.01 to 1.0, d = 0.01 to 1.0, e = 0.001 to 1.0, f = 0.001 to 1.0 and g depend on the oxidation state of atoms other than oxygen.

At the flame temperature, certain metal components, including Mo or Te, of the mixed metal oxide catalysts volatilize the remaining mixed metal oxidation catalysts, intermetallic catalysts, and their hybrid catalysts.

Another first catalyst includes phosphate catalysts including Mo, V, Nb and / or Ta (see Japanese Laid-Open Patent Application Publication No. 06-199731 A2).

Another first catalyst comprises _a mixed metal oxide having the structure P _a Mo _b V _c Bi _d X _e Y _f Z _g O _h , wherein X is As, Sb, Si, B, Ge or Te; Y is K, Cs, Rb, or Tl; Z is Cr, Mn, Fe, Co, Ni, Cu, Al, Ga, In, Sn, Zn, Ce, Y or W; a, b, c, d, e, f, g and h are the relative atomic weights of the elements; When b = 12, 0 <a≤3, c = 0-3, 0 <d≤3, 0 <e≤3, f = 0-3, g = 0-3 and h are in the oxidation state of other elements (See Japanese Laid-Open Patent Application Publication No. 09-020700 A2).

Other alternative mixed metal oxide catalysts can be used primarily usefully, which catalysts are described earlier in the description.

The second catalyst is useful for catalytic conversion of ethylenically unsaturated carboxylic acids to their corresponding esters.

The second catalyst comprises a superacid. According to Gillespie's definition, super acid means that the acidity value of Hammett, which is stronger than 100% sulfuric acid, has a H ₀ <−12 value. Representative superacids include zeolite supported TiO ₂ / (SO ₄ ) ₂ , (SO ₄ ) ₂ / ZrO ₂ -TiO ₂ , (SO ₄ ) ₂ / ZrO ₂ -Dy ₂ O ₃ , (SO ₄ ) ₂ / TiO ₂ , (SO ₄ ) ₂ / ZrO ₂ -NiO, SO ₄ / ZrO ₂ , SO ₄ / ZrO ₂ Al ₂ O ₃ , (SO ₄ ) ₂ / Fe ₂ O ₃ , (SO ₄ ) ₂ / ZrO ₂ , C ₄ F ₉ SO ₃ H-SbF ₅ , CF ₃ SO ₃ H-SbF ₅ , Pt / sulfate zirconium oxide, HSO ₃ F-SO ₂ ClF, SbF ₅ -HSO ₃ F-SO ₂ ClF, MF ₅ / AlF ₃ (M = Ta, Nb, Sb), B (OSO ₂ CF ₃ ) ₃ , B (OSO ₂ CF ₃ ) ₃ -CF ₃ SO ₃ H, SbF ₅ -SiO ₂ -Al ₂ O ₃ , SbF ₅ -TiO ₂ -SiO ₂ and SbF ₅ -TiO ₂ , but are not limited thereto. Preferably solid super acids are utilized, for example sulfate oxide supported Lewis acids and sulfate oxide supported liquid super acids. Only a small number of oxides, including ZrO ₂ , TiO ₂ , HfO ₂ , Fe ₂ O ₃ and SnO ₂ , form super acid sites in the sulfate. Acid sites are produced by treatment with amorphous oxyhydrate of this element with H ₂ SO ₄ or (NH ₄ ) ₂ SO ₄ and calcining the product at temperatures between 500 and 650 ° C. During firing, the oxide deforms into the crystalline tetragonal phase phase, which is covered by a small number of sulfate groups. H ₂ MoO ₄ or H ₂ WO ₄ can be used to activate the oxide.

Another alternative catalyst is described in U.S. Patent Nos. 3,825,600; Metal oxides mixed on the basis of well-known molybdenum, bismuth, iron, such as those disclosed in 3,649,930 and 4,339,335.

In another embodiment, a multistage process for producing esters of unsaturated carboxylic acids is provided, including: passing a first gas vapor comprising alkanes and molecular oxygen through a reactor; Passing a second gas vapor containing alcohol through the reactor; A reactor comprising at least one oxidation catalyst cumulatively effective to oxidize the alkane to the ester of the corresponding unsaturated carboxylic acid with alcohol; Esters of the first catalyst effective for oxidizing the alkanes to their corresponding alkenes, the second catalyst effective for oxidizing the alkenes to their corresponding unsaturated aldehydes, and unsaturated aldehydes in the presence of alcohols, with the corresponding unsaturated carboxylic acids with alcohols At least one oxidation catalyst comprising a third catalyst effective to oxidize with; The first catalyst is disposed in the first reaction zone; The second catalyst is disposed in the second reaction zone; The third catalyst is disposed in the third reaction zone; The first reaction zone is disposed in an upper portion of the second reaction zone in relation to the flow direction of the first gas vapor passing through the reactor; The second reaction zone is disposed upstream of the third reaction zone with respect to the flow direction of the first gas vapor through the reactor; The second gas vapor is fed into the reactor which mediates the second reaction zone and the third reaction zone; The first reaction zone is operated at a first reaction zone residence time of less than 100 milliseconds and at a temperature of 500 to 900 ° C .; The second reaction zone is operated at a second reaction zone residence time of less than 100 milliseconds and from 300 to 400 ° C; The third reaction zone is operated at a third reaction zone time of 100 milliseconds or less and at a temperature of 100 to 300 ° C.

In this aspect of the invention, it is useful to pass a first gaseous vapor comprising propane or isobutane and molecular oxygen to the SCR and to pass the corresponding alkene gaseous vapor to the SCTR; And it is useful to separately pass a second gas vapor containing alcohol into the SCTR. In addition, the feed may include auxiliaries such as steam or diluents such as inert gases (such as nitrogen, argon) or additional oxidants such as carbon dioxide.

Examples of sources of mild oxidants, including molecular oxygen or carbon dioxide, which can be applied during the process, are oxygen, oxygen-rich gases or air. Air may be the most economical source of oxygen, especially in the absence of reclaim.

Suitable catalysts are selected from each of the catalysts described previously. Other catalyst components are supported on a three-dimensional support structure, including a reducible metal oxide promoted with a metal selected from group 8 of the periodic table.

The support structure is three-dimensional, that is, the support is dimensioned along the x, y and z orthogonal axes of the Cartesian coordinate system and provides a relatively high surface area per unit volume. Although smaller and larger amounts are possible in one embodiment, the support structure exhibits a surface area of 0.01 to 50 m ² / g, preferably 0.1 to 10 m ² / g.

Preferably, the support structure has a porous structure and exhibits a void volume percentage of 1 to 95%, preferably 5 to 80%, more preferably 10 to 50%. Thus, the support structure allows for a high feed rate relative to a weak pressure drop.

In addition, the support structure is strong enough not to break up under the catalyst weight, so that up to almost 100% of the mixed weight of the catalyst and support structure does not break up. More preferably, the support structure is at least 60% of the mixing weight. More preferably 70 to 99.99% of the mixed weight. Even more preferably, the support structure is 90 to 99.9% of the mixed weight.

The exact physical form of the support structure is not particularly important as long as it meets the general criteria mentioned above. Examples of suitable physical forms include foams, honeycombs, grids, meshes, monoliths, woven fibers, woven fabrics, gauze, perforated materials (eg foils), tenants Compact, fibrous mats and mixtures thereof. In the support, typically at least one open cell should be included in the structure. Cell size can be varied as desired, depending on cell density, cell surface area, open front area, and other corresponding dimensions. For example, one such structure has an open front area of at least 75%. The shape of the cell may vary and may include polygonal shapes, circles, ellipses, and the like.

The support structure can be made of a material that is inert to the reaction environment of the catalytic reaction. Suitable materials include silica, alumina, silica-alumina, aluminosilicate, zirconia, titania, boria, mullite, lithium aluminium silicate, oxide-bonded silicon carbide, or mixtures thereof. Contains the same ceramics. (Alternatively, the catalyst is defined by the support structure itself, and can be produced, for example, by "green" compacting (compression) or other suitable technique.)

The catalyst can be applied to the support structure using techniques known in the art. For example, the catalyst may be gas deposited (eg, sputtering, plasma welding or other forms of gas deposition). The catalyst may be coated thereon (eg, by wash coating the support with a solution, slurry, suspension or dispersion of the catalyst). The support may be coated with catalyst powder (ie, powder coating). (Alternatively, the support structure may be compressed to produce a desired structure in which the "green" body of the catalyst, which is itself a catalyst.)

Suitable first catalyst is selected from the catalysts described above. Alternative first catalyst

It is also selected from the catalysts described previously. The alternative catalyst may be a bicomponent, tricomponent, tetracomponent or more metal oxide. Reducible metal oxides are Cu, Cr, V, Mn, Nb, Mo, W, Re, Ga, Ge, In, Sn, Sb, Tl, Pb, Bi, Te, As, Se, Zn, Y, Zr, Ta , Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and mixtures thereof. Preferably the reducible metal oxide is selected from the group consisting of Cu, Cr, V, Mn, Zn, and mixtures thereof. Promoto is a metal selected from the group 8 metals of the Periodic Table of the Elements (Fe, Ru, Os, Co, Rh, Ir, Ni, Pd and Pt), preferably Pt, Pd, Rh, Ir, Ru and mixtures thereof. It is selected from the configured group. The promoter is preferably present in an amount of 0.0001 to 10 wt% of the catalyst composition (promoter plus reducible metal oxide), more preferably 0.001 to 5 wt% of the catalyst composition, and more preferably of the catalyst composition Present in 0.01 to 2% by weight.

Suitable second catalysts are selected from those previously described. Alternative second catalysts are disclosed in U.S. Patent Nos. 3,825,600; Metal oxides mixed on a well-known molybdenum, bismuth, iron basis as disclosed in 3,649,930 and 4,339,335.

Suitable third catalyst is selected from the catalysts described previously. The third catalyst comprises a super acid. Superacids, according to Gillespie's definition, are super acids that are stronger than 100% sulfuric acid, that is, the Hammett acidity value is H _0. <-12 means to have a value. Representative superacids include zeolite supported TiO ₂ / (SO ₄ ) ₂ , (SO ₄ ) ₂ / ZrO ₂ -TiO ₂ , (SO ₄ ) ₂ / ZrO ₂ -Dy ₂ O ₃ , (SO ₄ ) ₂ / TiO ₂ , (SO ₄ ) ₂ / ZrO ₂ -NiO, SO ₄ / ZrO ₂ , SO ₄ / ZrO ₂ Al ₂ O ₃ , (SO ₄ ) ₂ / Fe ₂ O ₃ , (SO ₄ ) ₂ / ZrO ₂ , C ₄ F ₉ SO ₃ H-SbF ₅ , CF ₃ SO ₃ H-SbF ₅ , Pt / sulfate zirconium oxide, HSO ₃ F-SO ₂ ClF, SbF ₅ -HSO ₃ F-SO ₂ ClF, MF ₅ / AlF ₃ (M = Ta, Nb, Sb), B (OSO ₂ CF ₃ ) ₃ , B (OSO ₂ CF ₃ ) ₃ -CF ₃ SO ₃ H, SbF ₅ -SiO ₂ -Al ₂ O ₃ , SbF ₅ -TiO ₂ -SiO ₂ and SbF ₅ -TiO ₂ , but are not limited thereto. Preferably solid super acids are utilized, for example sulfate oxide supported Lewis acids and sulfate oxide supported liquid super acids. Only a small number of oxides, including ZrO ₂ , TiO ₂ , HfO ₂ , Fe ₂ O ₃ and SnO ₂ , form super acid sites in the sulfate. Acid sites are produced by treatment with amorphous oxyhydrate of this element with H ₂ SO ₄ or (NH ₄ ) ₂ SO ₄ and calcining the product at temperatures between 500 and 650 ° C. During firing, the oxide deforms into the crystalline tetragonal phase phase, which is covered by a small number of sulfate groups. H ₂ MoO ₄ or H ₂ WO ₄ can be used to activate the oxide.

In another embodiment of the present invention, there is provided a multi-step process for producing esters of unsaturated carboxylic acids, including the following methods: reacting unsaturated aldehydes with alcohols to form acetals; Passing the gas vapor including the formed acetal and oxygen molecules through the reactor; The reactor comprises at least one catalyst effective to oxidize acetal to its corresponding ester; The reactor is operated at reactor residence time of less than 100 milliseconds and at temperatures of 300 to 1000 ° C.

In another embodiment of the present invention, the alcohol is reacted with unsaturated aldehyde to form acetal. Such reactions are carried out by contacting with an excess of anhydrous alcohol in the presence of a small amount of anhydrous acid (eg hydrochloric anhydride). Preferably, the aldehyde and the alcohol pass through a bed containing an acid catalyst, for example a strong acid ion exchange resin (such as Amberlyst 15).

The acetal and molecular oxygen so formed are fed to a reactor comprising at least one catalyst effective to oxidize the acetal to its corresponding ester. Examples of the catalyst include Pd and Bi on alumina or V oxide.

In the aspect of the present invention, examples of the source of molecular oxygen that can be applied to the present invention are oxygen, a gas containing a large amount of oxygen, or air. Air can be the most economical source of oxygen, especially in the absence of reclaim.

 In another embodiment of the invention, unsaturated aldehydes are formed by oxidation of alkenes with their corresponding aldehydes. This oxidation can be effective as gas oxidation of alkanes in the presence of oxidation catalysts such as Pd and Bi on alumina or V oxides.

Example

Comparative Example 1 Wash coating Pt impregnated on Mo _a V _b M _c N _d Q _e X _f O _g onto alumina foam

An aqueous solution (200 mL) containing ammonium heptamolybdate tetrahydrate (1.0 M Mo), ammonium metavanadate (0.3 MV) and teruric acid (0.23 M Te) was made by dissolving the corresponding salt in 70 ° C., water. It was taken and placed in a 2000 mL rotavap flask. 200 mL of an aqueous solution of ammonium niobium oxalate (0.17 M Nb), oxalic acid (0.155 M), palladium nitrate hydrate (0.01 M Pd) and nitric acid (0.24 M HNO ₃ ) was added thereto. After the water was removed with a rotary evaporator under a water bath temperature of 50 ° C. and 28 mm Hg, the solid material was further dried overnight in a vacuum oven at 25 ° C. and then fired (with the solid material in air at 10 ° C./min). Heat to 275 ° C. and hold in air at 275 ° C. for one hour; then change the atmosphere to argon and heat the material to 600 ° C. at 275 ° C. to 2 ° C./min and heat the material at 600 ° C. for 2 hours. Calcined under argon.) The final catalyst has a composition of Mo _1.0 V _0.3 Te _0.23 Nb _0.17 Pd _0.01 O _x . Grind 30 g of catalyst and add 100 mL solution of 30% oxalic acid in water. As a result the suspension was stirred for 5 hours at 125 ° C. in a Parr reactor, at which time the solid was collected by gravity filtration and dried overnight in a vacuum oven, 25 ° C.

Subsequently dried material above 75 microns in size is impregnated with initial moisture with an aqueous solution of platinum acid to load 0.01 mole of Pt in relation to Mo. Excess water was removed using a rotary evaporator at a temperature of 50 ° C. and a pressure of 28 mm Hg and calcined in a quartz tube at 600 ° C. under an argon flow of 100 cc / min for 2 hours. As a result, the material was polished, 75 microns or less in size, suspended in acetone (1 g / 10 cc), and sonicated for 30 minutes. A 45 ppi alpha aluminum foam (Vesuvius Hi-Tech, 12 mm diameter and 0.5 cm thick dimension) is immersed in the stirring catalyst / acetone suspension, and nitrogen is no longer observed until mass additives are observed for the wash coated foam. It was then dried several times at room temperature. The other side of the foam was oriented during each cycle of wash coating preventing clogging of the foam. The result was a wash coating of 0.112 g and 20 wt% catalyst.

Comparative Example 2 Pt / In Oxide Supported on α-Alumina Foam Monolith

Alpha-Al ₂ O ₃ foam monolith (45 pores per inch) was applied as a support to prepare two sets of catalysts. The first set, including six catalysts, was formed from various proportions of platinum and indium oxides as specified in Table 1. Five aqueous solutions of 8% H ₂ PtCI ₆ (platinic acid) spiked various amounts of In (NO ₃ ) ₃ .5H ₂ O to give a mixture of platinum: indium as specified in Table 1. . The mixture was stirred at 40 ° C. until a homogeneous solution (about 30 minutes). Three monoliths were obtained for each of the five mixtures. The catalyst was prepared by immersing the monolith in the corresponding solution at room temperature for 1 hour, undergoing a drying step (100 ° C., 1 hour, under nitrogen), and firing step (600 ° C., 4 hours, in air). This process was repeated twice (the "pearl" process). One catalyst of this series (Pt: In = 1: 1.78) was prepared via another method “continuous coating method”. In this method, the monolith was first treated with indium nitrate solution for 1 hour, followed by drying and firing steps as mentioned above. This was done by a platinum coating step. Mass and% metal loadings are summarized in Table 1.

Table 1. Aluminum foam-platinum / indium oxide catalysts

* "Continuous way"

** Weight of 3 monoliths

Comparative Example 3 Pt / Nb Oxide Supported on α-Alumina Foam Monolith

Alpha-Al ₂ O ₃ foam monolith (45 pores per inch) was applied as a support to prepare two sets of catalysts. The first set, including six catalysts, was formed from various proportions of platinum and niobium oxides as specified in Table 2. Five aqueous solutions of 8% H ₂ PtCI ₆ (platinic acid) were spiked with varying amounts of ammonium niobium oxalate (0.17 M Nb) to give a mixture of platinum: niobinium specified in Table 1. Generated. The mixture was stirred at 40 ° C. until a homogeneous solution (about 30 minutes). Three Modolis were obtained for each of the five mixtures. The catalyst was prepared by immersing the monolith in the corresponding solution at room temperature for 1 hour, undergoing a drying step (100 ° C., 1 hour, under nitrogen), and firing step (600 ° C., 4 hours, in air). This process was repeated twice (the "pearl" process). The results are summarized in Table 2.

 Table 2. Aluminum Foam-Platinum / Niobium Oxide Catalysts

Comparative Example 4 Pt / Nb / V Oxide Supported on α-Alumina Foam Monolith

Alpha-Al ₂ O ₃ foam monolith (45 pores per inch) was applied as a support to prepare a Pd-Nb-V catalyst. A solution of 8% Pd (palladium nitrate hydrate), 2% In (indium nitrate hydrated), 0.4% V (ammonium metavanadate), oxal acid tetraacid (5% by weight) was prepared at 40 ° C. Stirred at. Concentrated nitric acid was added to produce a homogeneous solution of pH 2.0. The catalyst was prepared by immersing the monolith in the corresponding solution at room temperature for 1 hour, undergoing a drying step (100 ° C., 1 hour, under nitrogen), and firing step (600 ° C., 4 hours, in air). This process was repeated twice, yielding 4.7% loading.

Comparative reactor data for propane conversion using a catalyst in the short contact time reactor (SCTR) of the present invention are shown in Table 3.

Table 3. SCTR propane data for the comparative catalyst system of the present invention

All catalysts were wish coated with 45 ppi alpha-aluminum foam, 5 mm long and 12 mm straight.

Table 4 summarizes the physical properties of the molten salt process for preparing mixed metal oxide catalysts and catalyst systems.

Table 4. Properties of Selected Metal Halides

Niobium Vanadium Tellurium Molybdenum salt mp (℃) salt mp (℃) salt mp (℃) salt mp (℃) NbBr ₅ 265 TeBr ₂ 210 NbCl ₅ 205 VCl ₄ -25.7 TeCl ₄ 224 MoCl ₅ 194 NbF ₅ 72

Multistage catalyst Example  One

The first catalyst is used for propane and molecular oxygen as fuel to produce a mild oxidant, carbon dioxide and vapor that reduces the temperature at which propane converts to propylene in a short contact time. The amount of propane sacrificed to produce fuel and carbon dioxide is sufficient to produce the amount of heat required for the second catalytic step (catalyzed dehydrogenation of propane to propylene) (5-30% by weight). Examples of the first catalyst include metals selected from group 8 in the form of gauze, mesh, weiss, Pt, Rh, Pd, Ir and mixtures thereof. The catalyst is supported or unsupported in tertiary structures, including foams, monoliths, coated channels or microreactors selected from silica, alumina, silicates, aluminosilicates and gioliots. The reaction is carried out at millisecond contact time and at temperatures above 700 ° C.

The exothermic reaction resulting from complete propane oxidation is provided as heat of the endothermic dehydrogenation of propane to propylene under steam cracking conditions. In addition, the hydrogen produced is used as fuel to convert alkanes to their corresponding alkenes. Another advantage of the present invention is the use of hydrogen as fuel in the conversion (corresponding to the amount of work of the C2 conversion reported by L. Schmidt et al.). Vapor cracking catalysts include activated zeolites, ZSM-5 (used for ion exchange), or substituted configurations to optimize cracking efficiency. Incorporation of phosphorus into ZSM-5 in Superflex technology has been reported to improve FCC performance at second residence times. The reaction is carried out at short contact times and at temperatures above 500 ° C. Emissions from the short contact times are directed to the third stage or to the catalyst structure for selective oxidation. It is also useful at this stage to add one or more additional oxidants selected from air, oxygen, carbon dioxide and nitrous oxide, including additional steam. Useful or preferred oxygenates produced are acrylic acid, acrolein, acrylic acid esters, methacrylic acid and methacrylic acid esters. Esters require additional steps for the alcohol and higher analogs also require suitable additional steps. Selective oxidation is carried out above 300 ° C. Mixed metal oxide catalysts are useful.

The multistage catalyst was placed in a series of tubular reactors with suitable catalyst stages as described. Additional heat can be supplied to the second and third stage catalysts necessary to obtain useful conversion yields. Integrated catalyst zones that integrate thermally to optimize energy balance can also be usefully applied. The structure may include effective heat exchange of materials including alloys of Fe—Cr—Al—oxides. The catalyst can be supported on aluminum monolith. Other types of staged catalysts may also be usefully applied.

Multistage catalyst system Example  2

 The isobutane is catalytically converted to methacrylic acid with a short contact time using the Pt / Na- [Fe] -ZSM-5 type. This catalyst proved to exhibit high selectivity by L. Schmidt et al, which converts propane to propylene in conventional oxidative dehydrogenation reactions. The small level addition of Pt makes the catalyst suitable for flame temperatures in the SCTR. Incorporation of phosphorus into ZSM-5 improves selectivity and yield at fixed alkane conversion. Gas vapor release is directed to the second catalyst zone for selective oxidation. It is also useful at this stage to add one or more additional oxidants selected from air, oxygen, carbon dioxide and nitrous oxide, including raw materials in the form of additional steam and oxidized hydrogen. In addition, the generated hydrogen is used as a fuel to convert alkanes to their corresponding alkenes. Another advantage of the present invention is the use of hydrogen as fuel in the conversion (corresponding to the amount of work of the C2 conversion reported by L. Schmidt et al.). Useful or preferred resulting oxygenates include methacrylic acid and methacrylic acid esters. Esters require additional steps for the alcohol and higher analogs also require suitable additional steps. Selective oxidation is carried out above 300 ° C. Mixed metal oxide catalysts are useful.

Claims (20)

delete delete delete delete delete delete delete delete delete delete (A) catalytically completely oxidizes C ₃ to C ₈ alkanes in a first reaction stage comprising a temperature of 500 ° C. to 1000 ° C. and a residence time no greater than 100 milliseconds to A first catalyst capable of producing and comprising at least one metal selected from Rh, Ir, Ni, Pd, Pt, Fe, Ru, Os and Co; (B) 500 ℃ to in the second reaction step, including 1000 ℃ temperature and 100 residence time of no more than milliseconds, in the presence of carbon dioxide, C ₃ ~ C ₃ to dehydrogenation in response to C ₈ alkanes catalytically ₈ ~ C to produce the alkene and, (a) at least one metal selected from Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, the group consisting of alloys thereof, and mixtures thereof; And (b) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, Group 1- 3 metals, lanthanide-based metals and mixtures thereof. Phosphorus second catalyst; And (C) selectively oxidizing the corresponding C ₃ -C ₈ alkenes in a third reaction step comprising a temperature of 300 ° C. to 400 ° C. to produce C ₃ -C ₈ oxygenates, Mo, And a third catalyst comprising a selective oxidation catalyst comprising at least one of an oxide of a metal selected from the group consisting of Fe, P, and V, A multi-staged catalyst system for converting C ₃ to C ₈ alkanes to corresponding C ₃ to C ₈ alkenes, corresponding C ₃ to C ₈ oxygenates and mixtures thereof. delete The method of claim 11, And wherein at least one of said first, second and third catalysts is impregnated on a metal oxide support. The method of claim 11, Wherein said at least one oxidation catalyst further comprises (c) at least one of an oxide of a metal selected from the group consisting of Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V and Zn. The method of claim 11, And the second catalyst further comprises a cracking catalyst. (a) C ₃ ~ C ₈ alkanes and molecular oxygen (O ₂ ) is mixed, the amount of molecular oxygen completely oxidize 5 to 30% by weight of the C ₃ ~ C ₈ alkanes to carbon dioxide and water vapor (water vapor) Generating stoichiometric amounts, wherein 5-30% by weight of the C ₃ -C ₈ alkanes are completely oxidized to produce carbon dioxide and water vapor; (b) mixing carbon dioxide, water vapor, and alkanes not completely oxidized by molecular oxygen (O ₂ ) in step (a) to form a mixed feed stream; And (c) contacting the mixed feed stream with at least one vapor cracking catalyst at a temperature between 700 ° C. and 1000 ° C. and a residence time no greater than 100 milliseconds to produce corresponding C ₃ -C ₈ alkenes. Multi-step process for preparing the corresponding C ₃ -C ₈ alkenes from C ₃ -C ₈ alkanes. The method of claim 16, The at least one steam cracking catalyst, the conversion to a C ₃ ~ C ₈ alkene to the corresponding C ₃ ~ C ₈ alkanes containing an effective catalyst system to incremental, The catalyst system comprises (1) at least one metal selected from the group consisting of Ag, Au, Ir, Ni, Pd, Pt, Rh, Ru, alloys thereof and mixtures thereof; And (2) at least one modifier selected from the group of metal oxides including metals Bi, In, Mg, P, Sb, Zr, Group 1- 3 metals, lanthanide-based metals and mixtures thereof. Multi-level method. The method of claim 17, Wherein said at least one vapor cracking catalyst further comprises (3) at least one of an oxide of a metal selected from the group consisting of Cd, Co, Cr, Cu, Fe, Mn, Ni, Nb, Ta, V, Zn and mixtures thereof. Way. (A) by performing a multi-step process for producing a C ₃ ~ C ₈ alkenes from the corresponding C ₃ ~ C ₈ alkane, according to claim 16, wherein generating the corresponding C ₃ ~ C ₈ alkene; And (B) contacting the corresponding C ₃ -C ₈ alkenes with at least one selective oxidation catalyst comprising at least one metal oxide comprising a metal selected from the group consisting of Mo, Fe, P, V and mixtures thereof Generating at least one of the corresponding C ₃ -C ₈ oxygenates selected from the group consisting of carboxylic acids and esters thereof; Gradually effective multi-step method for converting C ₃ to C ₈ alkanes to the corresponding C ₃ to C ₈ oxygenates. The method of claim 19, And wherein said selective oxidation catalyst is located downstream from said cracking catalyst.